Moved the members and groups to single option called members

Closes #25985

See merge request !8281

Resolve "Cannot reset or remove MR/Issues description templates"

Closes #26346

See merge request !8446

* master: (35 commits)
  Adds back removed class in merge request pipelines table
  Fix dropdown icon alignment
  Simplify HTML of mini pipeline graph and dropdown 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
  Adds CHANGELOG entry
  Removes unneeded `window` declaration
  Decreases font-size on login page
  Ensure internal Gitlab::Git references use the namespace
  Absorb gitlab_git
  Fix review comments.
  Add spec for note edit and fix one commented spec.
  Review fixes.
  Use gl.utils.isInViewport and improve gl.utils.animateToElement.
  Make sure elements share the same scope
  Hide edit warning element when form reverted.
  Remove unnecessary styling came from merge conflicts.
  Fix single note edit form specs.
  Separate edit form in Changes and Discussions tab.
  Fix warning styling for responsive design.
  Fix task list for single edit note widget changes.
  Fix notes spec.
  ...

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