Fix cross database transaction when blocking users

When blocking a user, CI related queries are executed after the user's
state transitions to the "blocked" state. This commit ensures those
queries don't run in the same transaction as is used to update the user.

This fixes https://gitlab.com/gitlab-org/gitlab/-/issues/346235

Changelog: fixed

app/models/user.rb

@@ -391,9 +391,11 @@ class User < ApplicationRecord
     # this state transition object in order to do a rollback.
     # For this reason the tradeoff is to disable this cop.
     after_transition any => :blocked do |user|
+      user.run_after_commit do
         Ci::DropPipelineService.new.execute_async_for_all(user.pipelines, :user_blocked, user)
         Ci::DisableUserPipelineSchedulesService.new.execute(user)
       end
+    end
 
     after_transition any => :deactivated do |user|
       next unless Gitlab::CurrentSettings.user_deactivation_emails_enabled