EE backport for new application settings update service

See merge request !8665

Fix spec failure due to timestamp ordering issue in mySQL

Closes #26622

See merge request !8778

Fix 500 error for Group#web_url method if nested group

See merge request !8743

Nested groups feature improvemetns

See merge request !8448

Update enviroments.md - example CURL requests had a typo in the URL

See merge request cd ../gdk-ee/

Enable HAML-LINT linters phase 2

Closes #22072

See merge request !8566

Fixed error with filter keyboard tests

See merge request !8777

Only show Merge Request button when user can create a MR

See merge request !8639

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Support notes without a project (personal snippets notes)

See merge request !8468

Issue filter now appends a space & the test wasn't taking this into
account when checking the value

Grapify last endpoint of the branches API

See merge request !8755

`can?` already includes the `feature_available?` check, so no need to
check this again.

In case Merge Requests are disabled on the project, no one should see
the Merge Request button.

The project was not public and this caused a 404. So the tests were
giving deceiving results.

By searching for the Merge Request button in `#content-body` this
is overcome, and also other Merge Request buttons (e.g. in the
sidebar) are ignored.

Make diff discussions more reliable

Closes #23646

See merge request !8378

Only render the list if it is visible

See merge request !8710

Fixed keyboard navigation not working in filtered search bar

Closes #26840

See merge request !8656

Add redis version to info rake task

See merge request !8283

Add an eslint rule to flag extra newlines

See merge request !8137

Create a util for normalizing headers on the frontend

See merge request !8750

Fixed tab index order on branch commits list page

Closes #26447

See merge request !8489

Add metric initializer spec

See merge request !8714

Resolve "Reveal Variables button may overrun width of screen"

Closes #25780

See merge request !8221

Fixing sort of Users so that users who never logged in will be displayed last

Closes #26468

See merge request !8637

adds avatar for discussion note

Closes #26854

See merge request !8734

fix broken image when doing offline update check(help page)

Closes #25982

See merge request !8355

Update buttons on pipelines page to be more accessible

Closes #26445

See merge request !8561

Make the time estimate migrations reversible

See merge request !8749