Remove cached_mr_widget feature flag

As discussed in https://gitlab.com/gitlab-org/gitlab/-/issues/332966#note_683932353,
we are no longer pursuing the approach. Because of that, we're
removing the feature flag.

Changelog: removed

app/views/projects/merge_requests/_widget.html.haml

-= cache_if(Feature.enabled?(:cached_mr_widget, @merge_request.project), [@merge_request.project, @merge_request, current_user], expires_in: 10.minutes) do
-  - artifacts_endpoint_placeholder = ':pipeline_artifacts_id'
+- artifacts_endpoint_placeholder = ':pipeline_artifacts_id'
 
-  = javascript_tag do
-    :plain
-      window.gl = window.gl || {};
-      window.gl.mrWidgetData = #{serialize_issuable(@merge_request, serializer: 'widget', issues_links: true)}
+= javascript_tag do
+  :plain
+    window.gl = window.gl || {};
+    window.gl.mrWidgetData = #{serialize_issuable(@merge_request, serializer: 'widget', issues_links: true)}
 
-      window.gl.mrWidgetData.artifacts_endpoint = '#{downloadable_artifacts_project_pipeline_path(@project, artifacts_endpoint_placeholder, format: :json)}';
-      window.gl.mrWidgetData.artifacts_endpoint_placeholder = '#{artifacts_endpoint_placeholder}';
-      window.gl.mrWidgetData.squash_before_merge_help_path = '#{help_page_path("user/project/merge_requests/squash_and_merge")}';
-      window.gl.mrWidgetData.ci_troubleshooting_docs_path = '#{help_page_path('ci/troubleshooting.md')}';
-      window.gl.mrWidgetData.mr_troubleshooting_docs_path = '#{help_page_path('user/project/merge_requests/reviews/index.md', anchor: 'troubleshooting')}';
-      window.gl.mrWidgetData.pipeline_must_succeed_docs_path = '#{help_page_path('user/project/merge_requests/merge_when_pipeline_succeeds.md', anchor: 'only-allow-merge-requests-to-be-merged-if-the-pipeline-succeeds')}';
-      window.gl.mrWidgetData.security_approvals_help_page_path = '#{help_page_path('user/application_security/index.md', anchor: 'security-approvals-in-merge-requests')}';
-      window.gl.mrWidgetData.license_compliance_docs_path = '#{help_page_path('user/compliance/license_compliance/index.md', anchor: 'policies')}';
-      window.gl.mrWidgetData.eligible_approvers_docs_path = '#{help_page_path('user/project/merge_requests/approvals/rules.md', anchor: 'eligible-approvers')}';
-      window.gl.mrWidgetData.approvals_help_path = '#{help_page_path("user/project/merge_requests/approvals/index.md")}';
-      window.gl.mrWidgetData.pipelines_empty_svg_path = '#{image_path('illustrations/pipelines_empty.svg')}';
-      window.gl.mrWidgetData.codequality_help_path = '#{help_page_path("user/project/merge_requests/code_quality", anchor: "code-quality-reports")}';
-      window.gl.mrWidgetData.false_positive_doc_url = '#{help_page_path('user/application_security/vulnerabilities/index')}';
-      window.gl.mrWidgetData.can_view_false_positive = '#{@merge_request.project.licensed_feature_available?(:sast_fp_reduction).to_s}';
-      window.gl.mrWidgetData.user_preferences_gitpod_path = '#{profile_preferences_path(anchor: 'user_gitpod_enabled')}';
-      window.gl.mrWidgetData.user_profile_enable_gitpod_path = '#{profile_path(user: { gitpod_enabled: true })}';
+    window.gl.mrWidgetData.artifacts_endpoint = '#{downloadable_artifacts_project_pipeline_path(@project, artifacts_endpoint_placeholder, format: :json)}';
+    window.gl.mrWidgetData.artifacts_endpoint_placeholder = '#{artifacts_endpoint_placeholder}';
+    window.gl.mrWidgetData.squash_before_merge_help_path = '#{help_page_path("user/project/merge_requests/squash_and_merge")}';
+    window.gl.mrWidgetData.ci_troubleshooting_docs_path = '#{help_page_path('ci/troubleshooting.md')}';
+    window.gl.mrWidgetData.mr_troubleshooting_docs_path = '#{help_page_path('user/project/merge_requests/reviews/index.md', anchor: 'troubleshooting')}';
+    window.gl.mrWidgetData.pipeline_must_succeed_docs_path = '#{help_page_path('user/project/merge_requests/merge_when_pipeline_succeeds.md', anchor: 'only-allow-merge-requests-to-be-merged-if-the-pipeline-succeeds')}';
+    window.gl.mrWidgetData.security_approvals_help_page_path = '#{help_page_path('user/application_security/index.md', anchor: 'security-approvals-in-merge-requests')}';
+    window.gl.mrWidgetData.license_compliance_docs_path = '#{help_page_path('user/compliance/license_compliance/index.md', anchor: 'policies')}';
+    window.gl.mrWidgetData.eligible_approvers_docs_path = '#{help_page_path('user/project/merge_requests/approvals/rules.md', anchor: 'eligible-approvers')}';
+    window.gl.mrWidgetData.approvals_help_path = '#{help_page_path("user/project/merge_requests/approvals/index.md")}';
+    window.gl.mrWidgetData.pipelines_empty_svg_path = '#{image_path('illustrations/pipelines_empty.svg')}';
+    window.gl.mrWidgetData.codequality_help_path = '#{help_page_path("user/project/merge_requests/code_quality", anchor: "code-quality-reports")}';
+    window.gl.mrWidgetData.false_positive_doc_url = '#{help_page_path('user/application_security/vulnerabilities/index')}';
+    window.gl.mrWidgetData.can_view_false_positive = '#{@merge_request.project.licensed_feature_available?(:sast_fp_reduction).to_s}';
+    window.gl.mrWidgetData.user_preferences_gitpod_path = '#{profile_preferences_path(anchor: 'user_gitpod_enabled')}';
+    window.gl.mrWidgetData.user_profile_enable_gitpod_path = '#{profile_path(user: { gitpod_enabled: true })}';
 
-  #js-vue-mr-widget.mr-widget
+#js-vue-mr-widget.mr-widget

config/feature_flags/development/cached_mr_widget.yml

----
-name: cached_mr_widget
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/61584
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/330803
-milestone: '13.12'
-type: development
-group: group::code review
-default_enabled: false