Pipelines graph HTML and CSS improvements  and bug fixing

Closes #26257

See merge request !8443

Merge branch '19966-api-call-to-move-project-to-different-group-fails-when-using-group-and-project-names-instead-of-id' into 'master'

Fix groups API to accept path when transferring a project

Closes #19966

See merge request !8408

Move admin deploy keys spinach to rspec

See merge request !8405

Merge branch '26261-post-api-v3-projects-idorproject-commits-commits-does-not-work-with-project-path' into 'master'

Fix Commits API to accept a Project path upon POST

Closes #26261

See merge request !8406

Refactor discussion edit widget to have only one at a time.

Closes #23227

See merge request !8356

Removes CustomEvent polyfill and tests

See merge request !8400

Decreases font-size on login page

See merge request !8454

Creates individual html for dropdown
Adds simplified  CSS for the new dropdown
Removes old CSS
Improves dropdown item in Chrome, Firefox and Safari
Use SCSS variables for colors.
Fix scss linter errors
Adds animation when the stage is hovered.
Adds back tooltip on dropdown toggle
Fixes broken tests
additional css changes to get more into direction of mockups

25701 standardize text colors

Closes #25701

See merge request !8383

Removes unneeded `window` declaration in environments related code

Closes #25725

See merge request !8456

Absorb gitlab_git

Closes #24374

See merge request !8447

UX Guide: add section on search box

See merge request !8429

UX Guide: Add new primary and secondary text colors

See merge request !8449

Explain why we have this monkey-patch

See merge request !8329

Add API route slack slash commands

Closes #25954

See merge request !8362

Removes invalid html and unneeded CSS to prevent shaking in the pipelines tab

Closes #26278

See merge request !8411

Terminal: Add TextEncoder and TextDecoder in terminal bundle.

Closes #25977

See merge request !8450

Since there are multiple instances of text editors on the current fixture file we will use the one that creates a comment.

if we are in the Merge Requests page, this change will clone existing note-edit-form and add a mr-discussion-edit-form class to cloned element so we will have two note-edit-form in place. One for Discussions tab one for Changes tab.

For MR page, we basically need two note-edit-form because you may want to edit your comment in both tabs at the same time and we shouldn't remove or discard note-edit-form in other tab.