Remove pipeline_name_search feature flag

This enables filtering of pipelines by name in the public pipelines
API.

Changelog: added

app/finders/ci/pipelines_finder.rb

@@ -149,9 +149,7 @@ def by_yaml_errors(items)
     # rubocop: enable CodeReuse/ActiveRecord
 
     def by_name(items)
-      return items unless
-        Feature.enabled?(:pipeline_name_search, project) &&
-          params[:name].present?
+      return items unless params[:name].present?
 
       items.for_name(params[:name])
     end

config/feature_flags/development/pipeline_name_search.yml

----
-name: pipeline_name_search
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/107086
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/385864
-milestone: '15.7'
-type: development
-group: group::delivery
-default_enabled: false

doc/api/pipelines.md

@@ -19,12 +19,7 @@ Read more on [pagination](rest/index.md#pagination).
 > - `name` in response [introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/115310) in GitLab 15.11 [with a flag](../administration/feature_flags.md) named `pipeline_name_in_api`. Disabled by default.
 > - `name` in request [introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/115310) in 15.11 [with a flag](../administration/feature_flags.md) named `pipeline_name_search`. Disabled by default.
 > - `name` in response [generally available](https://gitlab.com/gitlab-org/gitlab/-/issues/398131) in GitLab 16.3. Feature flag `pipeline_name_in_api` removed.
-
-FLAG:
-On self-managed GitLab, by default the `name` field in a request is ignored.
-To make it available, an administrator can [enable the feature flag](../administration/feature_flags.md)
-named `pipeline_name_search`.
-On GitLab.com, this feature is available.
+> - `name` in request [generally available](https://gitlab.com/gitlab-org/gitlab/-/issues/385864) in GitLab 16.9. Feature flag `pipeline_name_search` removed.
 
 List pipelines in a project. Child pipelines are not included in the results,
 but you can [get child pipeline](pipelines.md#get-a-single-pipeline) individually.

spec/finders/ci/pipelines_finder_spec.rb

@@ -259,16 +259,6 @@
           is_expected.to be_empty
         end
       end
-
-      context 'when pipeline_name_search feature flag is off' do
-        before do
-          stub_feature_flags(pipeline_name_search: false)
-        end
-
-        it 'ignores name parameter' do
-          is_expected.to contain_exactly(pipeline, pipeline_other)
-        end
-      end
     end
 
     describe 'ordering' do