Remove redundant allow_cross_joins_across_databases call

This issue has been resolved so we do not need this allowlist.

app/controllers/projects/merge_requests_controller.rb

@@ -135,9 +135,7 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
 
         set_pipeline_variables
 
-        ::Gitlab::Database.allow_cross_joins_across_databases(url: 'https://gitlab.com/gitlab-org/gitlab/-/issues/336891') do
         @number_of_pipelines = @pipelines.size
-        end
 
         render
       end
@@ -201,7 +199,6 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
 
     Gitlab::PollingInterval.set_header(response, interval: 10_000)
 
-    ::Gitlab::Database.allow_cross_joins_across_databases(url: 'https://gitlab.com/gitlab-org/gitlab/-/issues/336891') do
     render json: {
       pipelines: PipelineSerializer
         .new(project: @project, current_user: @current_user)
@@ -212,7 +209,6 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
       }
     }
   end
-  end
 
   def sast_reports
     reports_response(merge_request.compare_sast_reports(current_user), head_pipeline)

app/models/merge_request.rb

@@ -1409,10 +1409,8 @@ class MergeRequest < ApplicationRecord
   def has_ci?
     return false if has_no_commits?
 
-    ::Gitlab::Database.allow_cross_joins_across_databases(url: 'https://gitlab.com/gitlab-org/gitlab/-/issues/336891') do
     !!(head_pipeline_id || all_pipelines.any? || source_project&.ci_integration)
   end
-  end
 
   def branch_missing?
     !source_branch_exists? || !target_branch_exists?
@@ -1912,10 +1910,8 @@ class MergeRequest < ApplicationRecord
   end
 
   def find_actual_head_pipeline
-    ::Gitlab::Database.allow_cross_joins_across_databases(url: 'https://gitlab.com/gitlab-org/gitlab/-/issues/336891') do
     all_pipelines.for_sha_or_source_sha(diff_head_sha).first
   end
-  end
 
   def etag_caching_enabled?
     true