Merge branch 'fix-spam-submit-button' into 'master'

Also check if Akismet is enabled, before showing the `Submit as spam` button.

Fixes #21229

See merge request !5948

app/models/concerns/spammable.rb

@@ -23,7 +23,7 @@ module Spammable
   def submittable_as_spam?
     if user_agent_detail
-      user_agent_detail.submittable?
+      user_agent_detail.submittable? && current_application_settings.akismet_enabled
     else
       false
     end