Switch "Regenerate token" to button & prevent spamming

Replace the "Regenerate token" link with a real `<button>` for improved accessibility and native disabled styling.
The button is disabled when a token is present, preventing users from generating multiple tokens in rapid succession.
This change improves user experience and prevents token spamming.

Author: aaronskiba

app/views/devise/registrations/_v2_api_token.html.erb

@@ -23,11 +23,11 @@
       </div>
 
       <div class="form-control mb-3 col-xs-8">
-        <%= link_to _("Regenerate token"),
-                    api_v2_internal_user_access_token_path,
-                    method: :post,
-                    class: 'btn btn-secondary',
-                    remote: true %>
+        <%= button_tag _("Regenerate token"),
+              type: :submit,
+              class: 'btn btn-secondary',
+              disabled: token.present?,
+              data: { remote: true, url: api_v2_internal_user_access_token_path, method: :post } %>
       </div>
     <% else %>
       <div class="alert alert-warning">