Fix Error 500s when attempting to destroy a protected tag

Closes #36013

See merge request !13692

Due to a missing `on_delete: :cascade`, users would hit the error that
looked like:

```
PG::ForeignKeyViolation: ERROR: update or delete on table "protected_tags"
violates foreign key constraint "fk_rails_f7dfda8c51" on table
"protected_tag_create_access_levels" DETAIL: Key (id)=(1385) is still
referenced from table "protected_tag_create_access_levels". : DELETE FROM
"protected_tags" WHERE "protected_tags"."id" = 1385
```

Closes #36013

Make issuable filter dropdown style consistent

See merge request !13421

Correct repo.vue template

Closes #36415

See merge request !13452

Add current locale to commit partial cache key

Closes #36591

See merge request !13669

Merge branch 'pawel/update_prometheus_client_gem_to_improve_performance_when_rendering_metrics' into 'master'

Update prometheus mmap client library to fix performance issues when rendering many metrics.

See merge request !13674

Migrating from Clearcase docs

See merge request !13569

Merge branch '36630-activerecord-statementinvalid-pg-notnullviolation-error-null-value-in-column-a_mode-violates-not-null-constraint' into 'master'

Resolve "ActiveRecord::StatementInvalid: PG::NotNullViolation: ERROR:  null value in column "a_mode" violates not-null constraint"

Closes #36630

See merge request !13663

[ci skip]

Describe the supported version of group-level variables API in document

Closes #36543

See merge request !13648

Update project_snippets.md

See merge request !13654

Guess the modes based on the following:

1. If the file didn't exist, it's zero.
2. If the diff contains 'Subproject commit', it might be a submodule, so 0600.
3. Otherwise, it's 0644.

This isn't perfect, but it doesn't have to be - it won't change file modes in
the repository.

Client Implementation: RefService::RefExists

Closes gitaly#452

See merge request !13528

Fix unnecessarily long gl.utils.backOff test

Closes #36648

See merge request !13651

Add support for i18n on Project Activity Page

Closes #32795

See merge request !13451

Setup settings properly

See merge request !13645

Don't escape html entities in InlineDiffMarkdownMarker

Closes #36041

See merge request !13553

Gitaly apply gitattributes

Closes gitaly#464

See merge request !13517

Updates for proper obj notation.

See merge request !13430

API: do not set rel="next" pagination header when no records found

Closes #36618

See merge request !13629

Fix external link to Composer website

Closes #36611

See merge request !13621

Make admin user actions dropdown consistent

See merge request !13630

Fixes the blown up emoji problem in notes

Closes #36448 and #36282

See merge request !13632

Properly explain when advanced Docker options were introduced

See merge request !13608

Docs: article - "Numerous undo possibilities in Git"

Closes gitlab-com/community-writers#40

See merge request !13513

And the link to the last page cannot be `page=0`.

Add specs that check the 'Link' header for the inclusion of:

 - rel="first"
 - rel="last"
 - rel="prev"
 - rel="next"

Fixes gitlab-org/gitlab-ce#36618

Related to gitlab-com/infrastructure#2532