Fix confirmation e-mails when signing up through an app (mastodon#29064)

Author: Gargron

app/views/user_mailer/confirmation_instructions.html.haml

@@ -8,9 +8,7 @@
           %td.email-inner-card-td.email-prose
             %p= t @resource.approved? ? 'devise.mailer.confirmation_instructions.explanation' : 'devise.mailer.confirmation_instructions.explanation_when_pending', host: site_hostname
             - if @resource.created_by_application
-              = render 'application/mailer/button', text: t('settings.account_settings'), url: edit_user_registration_url
-              = link_to confirmation_url(@resource, confirmation_token: @token, redirect_to_app: 'true') do
-                %span= t 'devise.mailer.confirmation_instructions.action_with_app', app: @resource.created_by_application.name
+              = render 'application/mailer/button', text: t('devise.mailer.confirmation_instructions.action_with_app', app: @resource.created_by_application.name), url: confirmation_url(@resource, confirmation_token: @token, redirect_to_app: 'true')
             - else
               = render 'application/mailer/button', text: t('devise.mailer.confirmation_instructions.action'), url: confirmation_url(@resource, confirmation_token: @token)
             %p= t 'devise.mailer.confirmation_instructions.extra_html', terms_path: about_more_url, policy_path: privacy_policy_url