Fix CAPTCHA page not following design pattern of sign-up flow (#25395)

app/controllers/concerns/captcha_concern.rb

@@ -2,6 +2,7 @@
 
 module CaptchaConcern
   extend ActiveSupport::Concern
+
   include Hcaptcha::Adapters::ViewMethods
 
   included do
@@ -35,18 +36,22 @@ module CaptchaConcern
         flash.delete(:hcaptcha_error)
         yield message
       end
+
       false
     end
   end
 
   def extend_csp_for_captcha!
     policy = request.content_security_policy
+
     return unless captcha_required? && policy.present?
 
     %w(script_src frame_src style_src connect_src).each do |directive|
       values = policy.send(directive)
+
       values << 'https://hcaptcha.com' unless values.include?('https://hcaptcha.com') || values.include?('https:')
       values << 'https://*.hcaptcha.com' unless values.include?('https://*.hcaptcha.com') || values.include?('https:')
+
       policy.send(directive, *values)
     end
   end

app/javascript/styles/mastodon/forms.scss

@@ -1048,7 +1048,9 @@ code {
 }
 
 .simple_form .h-captcha {
-  text-align: center;
+  display: flex;
+  justify-content: center;
+  margin-bottom: 30px;
 }
 
 .permissions-list {

app/views/auth/confirmations/captcha.html.haml

@@ -7,10 +7,12 @@
   = hidden_field_tag :confirmation_token, params[:confirmation_token]
   = hidden_field_tag :redirect_to_app, params[:redirect_to_app]
 
+  %h1.title= t('auth.captcha_confirmation.title')
   %p.lead= t('auth.captcha_confirmation.hint_html')
 
-  .field-group
-    = render_captcha
+  = render_captcha
+
+  %p.lead= t('auth.captcha_confirmation.help_html', email: mail_to(Setting.site_contact_email, nil))
 
   .actions
-    %button.button= t('challenge.confirm')
+    = button_tag t('challenge.confirm'), class: 'button', type: :submit