Update Prometheus documentation for 9.4

Closes #35129

See merge request !12885

Update Prometheus admin documentation for 9.4 - docs

Closes #35175

See merge request !12903

Update Gitaly Server Version to 0.21.2

See merge request !12937

reset text-align to initial to let elements with dir="auto" align texts to right…

Closes #13281

See merge request !12892

Add a foreign key to `merge_requests.head_pipeline_id`

Closes #34065

See merge request !12837

Resolve "Test/Production environment imparity in nokogiri"

Closes #34915

See merge request !12842

Add RequestCache to cache via RequestStore

See merge request !12920

Protect manual actions against protected tag too

Closes #34927

See merge request !12908

Perf: Improve performance of basic ruby ops in DeclarativePolicy

See merge request !12922

fix transient rspec failure due to Poll.js race condition

Closes #35225

See merge request !12930

Renamed Gitaly services

Closes gitaly#379

See merge request !12854

Update 9.3-to-9.4.md

See merge request !12925

don't treat aborted requests as failures, they are often triggered during unload (e.g after clicking a link)

Refactor variables initialization in dropzone_input.js

Closes #29901

See merge request !12768

Remove coffee-rails gem

Closes #34831

See merge request !12715

fix padding on filtered search

Closes #35177

See merge request !12913

We also try to use instance variable to cache the result if
RequestStore is not available, so we could keep the same logic,
using the same cache key. Also introduce a way to specify method
specific cache key