Merge branch '39791-when-reopening-an-issue-the-mattermost-notification-has-no-context-to-the-issue' into 'master'

Resolve "When reopening an issue the Mattermost Notification has no context to the issue"

Closes #39791

See merge request gitlab-org/gitlab-ce!15218

Merge branch '37442-api-branches-id-repository-branches-is-calling-gitaly-n-1-times-per-request' into 'master'

Fetch the merged branches at once in the `/projects/:id/repository/branches` endpoint

See merge request gitlab-org/gitlab-ce!15215

Support custom attributes on groups and projects

See merge request gitlab-org/gitlab-ce!14593

Add changes_count to the merge requests API

See merge request gitlab-org/gitlab-ce!15178

First iteration of Move Kubernetes from service to Cluster page

See merge request gitlab-org/gitlab-ce!15061

[CE backport] Saved configuration for issue board

See merge request gitlab-org/gitlab-ce!15108

Label priority and Priority sort orders

See merge request gitlab-org/gitlab-ce!15219

Fix GFM reference links for closed milestones

Closes #39850

See merge request gitlab-org/gitlab-ce!15234

Change tags order in refs dropdown

Closes #37336

See merge request gitlab-org/gitlab-ce!15235

Updates CE metrics with updated versions from EE

See merge request gitlab-org/gitlab-ce!15229

Enable multiple queries per Prometheus graph

See merge request gitlab-org/gitlab-ce!15201

fix borderzero lint

See merge request gitlab-org/gitlab-ce!15233

Updates CE metrics with updated versions from EE for supported metrics (EE version includes additional items for EE specific features)

Convert copy_as_gfm into ES module and move to behaviors

See merge request gitlab-org/gitlab-ce!14859

34768 Fix problem with issuable header wrapping when content is too long

Closes #34768

See merge request gitlab-org/gitlab-ce!15192

Fixes 404 error to `Issues assigned to me` and `Issues I've created` when issues are disabled

Closes #20666

See merge request gitlab-org/gitlab-ce!15021

Merge remote-tracking branch 'origin/move-kubernetes-from-service-to-clusters-page-10-2-ver' into 35616-move-gke-form-1st-iteration

Refactor Clusters to be consisted from GcpProvider and KubernetesPlatform

See merge request gitlab-org/gitlab-ce!14879

Add all InfluxDB metrics to prometheus

See merge request gitlab-org/gitlab-ce!13891

Fixup rspec tag misuse

See merge request gitlab-org/gitlab-ce!15227

The dropdown options `Issues assigned to me` and `Issues I've created` in project search are now
hidden when issues are disabled on the project.

Fix md form tab double click toggle

Closes #39624

See merge request gitlab-org/gitlab-ce!15119