DPC-5177 Button link fix (#2924)

## 🎫 Ticket

https://jira.cms.gov/browse/DPC-5177

## 🛠 Changes

Updates button link/handling so that buttons that behaved as links are
now just links

```html
<form method="GET" action="/some-path">
   <button>Click me</button>
</form>
```
becomes
```html
<a href="/some-path">Click me</a>
```

Also updates `button_to` component handling to set method back to the
default of POST to avoid incorrect usage going forward.

## ℹ️ Context

We were incorrectly using submit buttons which behave differently than
expected than links for screen reader users and those who use assistive
technology. This makes links semantically consistent.

## 🧪 Validation

Verified during development using Lookbook

[A11y
check](https://github.com/CMSgov/dpc-app/actions/runs/22684903996/job/65765091219)
- This change isn't caught by automated semantic HTML check, so we
remain at 11 issues

Author: jhutchison-nava

dpc-portal/app/components/core/button/button_component.rb

@@ -6,7 +6,7 @@ module Button
     class ButtonComponent < ViewComponent::Base
       attr_accessor :label, :destination, :method, :additional_classes
 
-      def initialize(label:, destination:, method: :get, additional_classes: nil, disabled: false)
+      def initialize(label:, destination:, method: :post, additional_classes: nil, disabled: false)
         super
         @label = label
         @destination = destination

dpc-portal/app/components/core/card/basic_component.html.erb

@@ -6,7 +6,7 @@
       </div>
       <div class="flex-align-self-center">
         <% if @button_params %>
-          <%= button_to @button_params[:name], @button_params[:path], method: @button_params[:method], class: 'usa-button' %>
+          <%= link_to @button_params[:name], @button_params[:path], class: 'usa-button' %>
         <% end %>
       </div>
     </div>

dpc-portal/app/components/page/invitations/accept_invitation_component.html.erb

@@ -11,14 +11,12 @@
         </ul>
       </p>
     <%= render Core::Button::ButtonComponent.new(label: 'Verify information',
-        destination: confirm_organization_invitation_path(@organization, @invitation),
-        method: :post) %>
+        destination: confirm_organization_invitation_path(@organization, @invitation)) %>
     <% end %>
     <% if @invitation.credential_delegate? %>
     <p>Your identity has been verified. You can now accept your invite</p>
     <%= render Core::Button::ButtonComponent.new(label: 'Accept invite',
-        destination: register_organization_invitation_path(@organization, @invitation),
-        method: :post) %>
+        destination: register_organization_invitation_path(@organization, @invitation)) %>
     <% end %>
   </div>
 </div>

dpc-portal/app/components/page/invitations/ao_flow_fail_component.html.erb

@@ -10,8 +10,6 @@
   <p><%=raw t(key=@text, org_name: @org_name) %></p>
   <% 'have to put statement here, as do not have route helper in ViewComponent'
     if @reason == :fail_to_proof %>
-      <%= render Core::Button::ButtonComponent.new(label: 'Go to DPC Portal',
-        destination: root_url,
-        method: :get) %>
+      <%= link_to 'Go to DPC Portal', new_user_session_path, class: 'usa-button margin-bottom-3' %>
     <% end %>
 </div>

dpc-portal/app/components/page/invitations/invitation_login_component.html.erb

@@ -8,8 +8,6 @@
       <% end %>
     </ul>
   </p>
-  <%= button_to login_organization_invitation_url(@invitation.provider_organization, @invitation), class: 'usa-button margin-bottom-1 margin-top-2', data: { turbo: false } do %>
-  Verify my identity
-  <% end %>
+    <%= button_to 'Verify my identity', login_organization_invitation_url(@invitation.provider_organization, @invitation), class: 'usa-button margin-bottom-1 margin-top-2', data: { turbo: false } %>
   <div><%= link_to 'How to verify your identity', 'https://login.gov/help/verify-your-identity/how-to-verify-your-identity/', target: :_blank %> <%= link_to 'Login.gov FAQ', 'https://www.login.gov/help/', target: :_blank, class: 'margin-left-2' %></div>
 </div>

dpc-portal/app/components/page/invitations/register_component.html.erb

@@ -3,7 +3,6 @@
   <div>
     <p>Your role as Authorized Official and your organization's Medicare enrollment have been verified.</p>
     <%= render Core::Button::ButtonComponent.new(label: "Submit registration",
-        destination: register_organization_invitation_path(@organization, @invitation),
-        method: :post) %>
+        destination: register_organization_invitation_path(@organization, @invitation)) %>
   </div>
 </div>

dpc-portal/app/components/page/invitations/start_component.html.erb

@@ -44,14 +44,8 @@
             <% end %>
           </ul>
         </p>
-        <%= render Core::Button::ButtonComponent.new(label: 'Begin registration',
-            destination: accept_organization_invitation_path(@organization, @invitation),
-                                                     additional_classes: ['start-component-button'],
-            method: :get) if @invitation.authorized_official? %>
-        <%= render Core::Button::ButtonComponent.new(label: 'Get Started',
-            destination: confirm_cd_organization_invitation_path(@organization, @invitation),
-                                                     additional_classes: ['start-component-button'],
-            method: :get) if @invitation.credential_delegate? %>
+        <%= link_to 'Begin registration', accept_organization_invitation_path(@organization, @invitation), class: 'usa-button start-component-button' if @invitation.authorized_official? %> 
+        <%= link_to 'Get Started', confirm_cd_organization_invitation_path(@organization, @invitation), class: 'usa-button start-component-button' if @invitation.credential_delegate? %> 
       </div>
     </div>
   </div>

dpc-portal/app/components/page/invitations/success_component.html.erb

@@ -23,7 +23,5 @@
       <% end %>
   </ul>
   <% end %>
-  <%= render Core::Button::ButtonComponent.new(label: 'Go to DPC Portal',
-      destination: root_url,
-      method: :get) %>
+  <%= link_to 'Go to DPC Portal', new_user_session_path, class: 'usa-button margin-right-0' %>
 </div>

dpc-portal/app/components/page/organization/credentials_component.html.erb

@@ -1,6 +1,6 @@
 <div id="credentials">
   <%= render(Core::Card::BasicComponent.new(text_content: '<h2>Client tokens</h2>',
-      button_params: { name: 'Generate token', path: new_organization_client_token_path(@organization.path_id), method: :get} )) do %>
+      button_params: { name: 'Generate token', path: new_organization_client_token_path(@organization.path_id)} )) do %>
     <div>
       <p>Client tokens monitor who's accessing the API with your organization credentials.</p>
       <% if @organization.client_tokens.present? %>
@@ -17,7 +17,7 @@
     </div>
   <% end %>
   <%= render(Core::Card::BasicComponent.new(text_content: '<h2>Public keys</h2>',
-      button_params: { name: 'Add key', path: new_organization_public_key_path(@organization.path_id), method: :get} )) do %>
+      button_params: { name: 'Add key', path: new_organization_public_key_path(@organization.path_id) } )) do %>
     <div>
       <p>Public keys verify that client token requests come from an authorized application.</p>
       <% if @organization.public_keys.present? %>
@@ -35,7 +35,7 @@
   <% end %>
 
   <%= render(Core::Card::BasicComponent.new(text_content: '<h2>Public IP addresses</h2>',
-      button_params: { name: 'Add IP', path: new_organization_ip_address_path(@organization.path_id), method: :get} )) do %>
+      button_params: { name: 'Add IP', path: new_organization_ip_address_path(@organization.path_id)} )) do %>
     <div>
       <p>Provide a maximum of 8 public IP addresses associated with systems that will access claims data.</p>
       <% if @organization.public_ips.present? %>

dpc-portal/app/components/page/organization/new_organization_success_component.html.erb

@@ -16,7 +16,7 @@
   <div class="margin-top-5">
     <div class="display-flex flex-row flex-start" style="gap:20px;">
         <div class="flex-align-self-center">
-            <%= render Core::Button::ButtonComponent.new(label: 'Assign CD now', destination: new_organization_credential_delegate_invitation_path(@organization))%>
+            <%= link_to 'Assign CD now', new_organization_credential_delegate_invitation_path(@organization), class: 'usa-button margin-right-0' %>
         </div>
         <div class="flex-align-self-center">
             <%= link_to 'Assign CD later', root_path %>