Only check for modified paths when the branch is updated

Changelog: fixed
MR: gitlab.com/gitlab-org/gitlab/-/merge_requests/63523
EE: true

ee/app/services/ee/merge_requests/refresh_service.rb

@@ -49,7 +49,7 @@ module EE
       end
 
       def code_owners_updated?
-        return if push.branch_removed?
+        return unless push.branch_updated?
 
         push.modified_paths.find { |path| ::Gitlab::CodeOwners::FILE_PATHS.include?(path) }
       end

ee/spec/services/ee/merge_requests/refresh_service_spec.rb

@@ -128,6 +128,12 @@ RSpec.describe MergeRequests::RefreshService do
 
             it_behaves_like 'does not refresh the code owner rules'
           end
+
+          context 'when the branch is created' do
+            let(:oldrev) { Gitlab::Git::BLANK_SHA }
+
+            it_behaves_like 'does not refresh the code owner rules'
+          end
         end
 
         context 'when the branch is not protected' do