Merge branch 'remove-joins-pipelinesfinder-by-username' into 'master'

Avoid join in PipelinesFinder#by_username

See merge request gitlab-org/gitlab!66023

app/finders/ci/pipelines_finder.rb

@@ -119,11 +119,12 @@ module Ci
 
     # rubocop: disable CodeReuse/ActiveRecord
     def by_username(items)
-      if params[:username].present?
-        items.joins(:user).where(users: { username: params[:username] })
-      else
-        items
-      end
+      return items unless params[:username].present?
+
+      user_id = User.by_username(params[:username]).pluck_primary_key.first
+      return Ci::Pipeline.none unless user_id
+
+      items.where(user_id: user_id)
     end
     # rubocop: enable CodeReuse/ActiveRecord