Backport avatar-related spec changes from gitlab-org/gitlab-ee@4b464eaaee

See merge request !11072

Added rescue block for the test method for the prometheus service

Closes #31451

See merge request !10994

Expect latency to be non-negative number.

Closes #31747

See merge request !11116

Fix email receiver metrics events

See merge request !11112

Fixed avatar not displaying in issue boards

Closes #31428

See merge request !10977

Add instant comments support

Closes #27614

See merge request !10760

Resolve: "Pipelines: When we retry a pipeline 2 requests are made to the pipelines endpoint"

Closes #30237

See merge request !10584

`Project#inspect` isn't very useful for examining usage of these features.

Sometimes the tests run so fast latency is calculated as 0.
This causes transient failures in our CI.

Fixed bug where merge request JSON would show

Closes #28909

See merge request !11096

Display slash commands outcome when previewing Markdown

Closes #21531

See merge request !10054

Resolve "Documentation: Frontend list of do's and don'ts"

Closes #31552

See merge request !11091

Add a manual job to trigger package build in omnibus

Closes omnibus-gitlab#2234

See merge request !11086

Update design of auth error page

Closes #29145

See merge request !11099

Remove # char for commit

Closes #31810

See merge request !11093

This makes it possible to workaround a bug in `safe_constantize` which
caused a `LoadError` exception when doing

```
"Pipeline".safe_constantize
LoadError: Unable to autoload constant Pipeline, expected
/home/grzesiek/gdk/gitlab/app/models/ci/pipeline.rb to define it
```

See https://github.com/rails/rails/issues/28854 for more details.

Internationalise Cycle Analytics page

Closes #28433

See merge request !10669

Conflicts:
	lib/gitlab/cycle_analytics/review_stage.rb
	lib/gitlab/cycle_analytics/staging_stage.rb
	lib/gitlab/cycle_analytics/test_stage.rb

Fix wording of Cycle Analytics stage legends

See merge request !11106

Port of "2274-store-last-repository-updated-at" to CE

See merge request !11085

Resolve "Web GUI: Unable to create new branch from commit SHA"

Closes #30329

See merge request !10738

Fix MR target branch select dropdown placement cut-off

Closes #31271

See merge request !10902