Fix failing shibboleth test

This change attempts to resolve the following error:

```
  1) Email Confirmation A user attempts to sign in via the "Sign in with your institutional credentials"
            button. The email is linked to a user account, however the account is
            unconfirmed and has no confirmation token.
     Failure/Error: raise ActionNotFound.new("The action '#{action}' could not be found for #{self.class.name}", self, action)

     AbstractController::ActionNotFound:
       The action 'shibboleth' could not be found for Users::OmniauthCallbacksController

```
The Users::OmniauthCallbacksController#shibboleth action is defined dynamically within the controller. Everything is working locally with commit bcc8d1f, but the test is failing when executed as a GitHub Action.
This change attempts to make sure that the Shibboleth identifier_scheme is created before the corresponding dynamical shibboleth action is triggered during test execution.

Author: aaronskiba

spec/features/email_confirmation_spec.rb

@@ -26,34 +26,41 @@
     expect(page).to have_current_path(plans_path)
   end
 
-  scenario 'A user attempts to sign in via the "Sign in with your institutional credentials"
-            button. The email is linked to a user account, however the account is
-            unconfirmed and has no confirmation token.', :js do
-    user = create(:user, :unconfirmed_and_no_confirmation_token)
-    scheme = create(:identifier_scheme, :shibboleth)
-    # Mock the OmniAuth authentication hash for Shibboleth via OmniAuthHelper
-    OmniAuth.config.mock_auth[:shibboleth] = mock_auth_hash(user, scheme)
-    # Create a Shibboleth-related Identifier for the user
-    Identifier.create(identifier_scheme: scheme,
-                      value: OmniAuth.config.mock_auth[:shibboleth].uid,
-                      attrs: OmniAuth.config.mock_auth[:shibboleth],
-                      identifiable: user)
-
-    visit root_path
-    # Sign-in attempt #1 (user is unconfirmed and has no confirmation_token)
-    click_link SSO_SIGN_IN_BUTTON_TEXT
-    expectations_for_unconfirmed_user_with_no_confirmation_token_after_sign_in_attempt(user)
+  describe 'Initial setup for shibboleth sign-in' do
+    before do
+      # Set up the user and identifier scheme
+      @user = create(:user, :unconfirmed_and_no_confirmation_token)
+      @scheme = create(:identifier_scheme, :shibboleth)
 
-    visit root_path
-    # Sign-in attempt #2 (user still unconfirmed but has a confirmation_token)
-    click_link SSO_SIGN_IN_BUTTON_TEXT
-    expectations_for_unconfirmed_user_with_confirmation_token_after_sign_in_attempt
+      # Mock OmniAuth authentication hash for Shibboleth via OmniAuthHelper
+      OmniAuth.config.mock_auth[:shibboleth] = mock_auth_hash(@user, @scheme)
 
-    # Sign-in attempt #3 (user is now confirmed)
-    user.confirm
-    click_link SSO_SIGN_IN_BUTTON_TEXT
-    # The user is signed in
-    expect(page).to have_current_path(plans_path)
+      # Create the identifier for the user
+      Identifier.create(identifier_scheme: @scheme,
+                        value: OmniAuth.config.mock_auth[:shibboleth].uid,
+                        attrs: OmniAuth.config.mock_auth[:shibboleth],
+                        identifiable: @user)
+    end
+
+    scenario 'A user attempts to sign in via the "Sign in with your institutional credentials"
+              button. The email is linked to a user account, however the account is
+              unconfirmed and has no confirmation token.', :js do
+      visit root_path
+      # Sign-in attempt #1 (user is unconfirmed and has no confirmation_token)
+      click_link SSO_SIGN_IN_BUTTON_TEXT
+      expectations_for_unconfirmed_user_with_no_confirmation_token_after_sign_in_attempt(@user)
+
+      visit root_path
+      # Sign-in attempt #2 (user still unconfirmed but has a confirmation_token)
+      click_link SSO_SIGN_IN_BUTTON_TEXT
+      expectations_for_unconfirmed_user_with_confirmation_token_after_sign_in_attempt
+
+      # Sign-in attempt #3 (user is now confirmed)
+      @user.confirm
+      click_link SSO_SIGN_IN_BUTTON_TEXT
+      # The user is signed in
+      expect(page).to have_current_path(plans_path)
+    end
   end
 
   scenario 'A user is unconfirmed but has no confirmation token.