Clear cached_widget.json cache after merging

What does this MR do and why?

Related issue: #420934 (closed)

Related Jihu issue: https://jihulab.com/gitlab-cn/gitlab/-/issues/3383

What

Solve the cache invalidation problem of MR page: when MR is merged, the status of the merged Pipeline in MR will be cached for 20 minutes. Even if the Pipeline has been completed, it will still appear to be running on the MR page.

Here is a detailed background description: #420934 (comment 1731742676)

SQL Changes

Currently MR adds the following sql:

pry(main)> pipeline.project.merge_requests.by_merged_or_merge_or_squash_commit_sha(pipeline.sha)

  Project Load (0.8ms)  SELECT "projects"."id", "projects"."name", "projects"."path", "projects"."description", "projects"."created_at", "projects"."updated_at", "projects"."creator_id", "projects"."namespace_id", "projects"."last_activity_at", "projects"."import_url", "projects"."visibility_level", "projects"."archived", "projects"."avatar", "projects"."merge_requests_template", "projects"."star_count", "projects"."merge_requests_rebase_enabled", "projects"."import_type", "projects"."import_source", "projects"."approvals_before_merge", "projects"."reset_approvals_on_push", "projects"."merge_requests_ff_only_enabled", "projects"."issues_template", "projects"."mirror", "projects"."mirror_last_update_at", "projects"."mirror_last_successful_update_at", "projects"."mirror_user_id", "projects"."shared_runners_enabled", "projects"."runners_token", "projects"."build_allow_git_fetch", "projects"."build_timeout", "projects"."mirror_trigger_builds", "projects"."pending_delete", "projects"."public_builds", "projects"."last_repository_check_failed", "projects"."last_repository_check_at", "projects"."only_allow_merge_if_pipeline_succeeds", "projects"."has_external_issue_tracker", "projects"."repository_storage", "projects"."repository_read_only", "projects"."request_access_enabled", "projects"."has_external_wiki", "projects"."ci_config_path", "projects"."lfs_enabled", "projects"."description_html", "projects"."only_allow_merge_if_all_discussions_are_resolved", "projects"."repository_size_limit", "projects"."printing_merge_request_link_enabled", "projects"."auto_cancel_pending_pipelines", "projects"."service_desk_enabled", "projects"."cached_markdown_version", "projects"."delete_error", "projects"."last_repository_updated_at", "projects"."disable_overriding_approvers_per_merge_request", "projects"."storage_version", "projects"."resolve_outdated_diff_discussions", "projects"."remote_mirror_available_overridden", "projects"."only_mirror_protected_branches", "projects"."pull_mirror_available_overridden", "projects"."jobs_cache_index", "projects"."external_authorization_classification_label", "projects"."mirror_overwrites_diverged_branches", "projects"."pages_https_only", "projects"."external_webhook_token", "projects"."packages_enabled", "projects"."merge_requests_author_approval", "projects"."pool_repository_id", "projects"."runners_token_encrypted", "projects"."bfg_object_map", "projects"."detected_repository_languages", "projects"."merge_requests_disable_committers_approval", "projects"."require_password_to_approve", "projects"."max_pages_size", "projects"."max_artifacts_size", "projects"."pull_mirror_branch_prefix", "projects"."remove_source_branch_after_merge", "projects"."marked_for_deletion_at", "projects"."marked_for_deletion_by_user_id", "projects"."autoclose_referenced_issues", "projects"."suggestion_commit_message", "projects"."project_namespace_id", "projects"."hidden", "projects"."organization_id" FROM "projects" WHERE "projects"."id" = 18 LIMIT 1 /*application:console,db_config_name:main,console_hostname:192.168.1.105,console_username:deer,line:(pry):20:in `__pry__'*/
  MergeRequest Load (1.1ms)  SELECT "merge_requests".* FROM ((SELECT "merge_requests".* FROM "merge_requests" WHERE "merge_requests"."target_project_id" = 18 AND "merge_requests"."squash_commit_sha" = '\x3df57d6de329345929e15768bc6692edf77c0f05')
UNION
(SELECT "merge_requests".* FROM "merge_requests" WHERE "merge_requests"."target_project_id" = 18 AND "merge_requests"."merge_commit_sha" = '3df57d6de329345929e15768bc6692edf77c0f05')
UNION
(SELECT "merge_requests".* FROM "merge_requests" WHERE "merge_requests"."target_project_id" = 18 AND "merge_requests"."merged_commit_sha" = '\x33646635376436646533323933343539323965313537363862633636393265646637376330663035')) merge_requests WHERE "merge_requests"."target_project_id" = 18 /*application:console,db_config_name:main,console_hostname:192.168.1.105,console_username:deer,line:bin/rails:4:in `<main>'*/

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

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Before	After

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cc @chaomao @xfyuan