Use text-decoration-done styling for mailer branding platform name link

Author: rsmithlal

app/views/layouts/better_together/mailers/_navbar_brand.html.erb

@@ -1,7 +1,7 @@
 
 <%= cache ['mailer_header_branding', host_community.cache_key_with_version] do %>
   <!-- Branding Element -->
-  <%= link_to base_url_with_locale, class: 'navbar-brand' do %>
+  <%= link_to base_url_with_locale, class: 'navbar-brand text-decoration-none' do %>
     <% if host_community.logo.attached? %>
       <%= image_tag rails_storage_proxy_url(host_community.optimized_logo), class: "#{dom_class(host_community, :host)}_logo", title: host_community.name, alt: host_community.name %>
     <% else %>