Quarantine MR fork spec test

Failing and blocking deployments

qa/qa/specs/features/browser_ui/3_create/merge_request/merge_merge_request_from_fork_spec.rb

@@ -2,7 +2,7 @@
 module QA
   RSpec.describe 'Create' do
-    describe 'Merge request creation from fork', :smoke do
+    describe 'Merge request creation from fork', :smoke, quarantine: { issue: 'https://gitlab.com/gitlab-org/gitlab/-/issues/324304', type: :investigating } do
       let!(:merge_request) do
         Resource::MergeRequestFromFork.fabricate_via_browser_ui! do |merge_request|
           merge_request.fork_branch = 'feature-branch'