Remove FF ci_modified_paths_of_external_prs

It's already enabled by default since 14.2

Changelog: other

app/models/ci/pipeline.rb

@@ -1107,7 +1107,7 @@ module Ci
           merge_request.modified_paths
         elsif branch_updated?
           push_details.modified_paths
-        elsif external_pull_request? && ::Feature.enabled?(:ci_modified_paths_of_external_prs, project, default_enabled: :yaml)
+        elsif external_pull_request?
           external_pull_request.modified_paths
         end
       end

config/feature_flags/development/ci_modified_paths_of_external_prs.yml

----
-name: ci_modified_paths_of_external_prs
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/60736
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/330605
-milestone: '13.12'
-type: development
-group: group::pipeline authoring
-default_enabled: true

spec/models/ci/pipeline_spec.rb

@@ -2037,16 +2037,6 @@ RSpec.describe Ci::Pipeline, :mailer, factory_default: :keep do
       it 'returns external pull request modified paths' do
         expect(pipeline.modified_paths).to match(external_pull_request.modified_paths)
       end
-
-      context 'when the FF ci_modified_paths_of_external_prs is disabled' do
-        before do
-          stub_feature_flags(ci_modified_paths_of_external_prs: false)
-        end
-
-        it 'returns nil' do
-          expect(pipeline.modified_paths).to be_nil
-        end
-      end
     end
   end