Limit autocomplete to currently selected items

What does this MR do?

When using the /unlabel command the autocomplete list of labels is nowlimited to the list of labels currently assigned to the issue.

Are there points in the code the reviewer needs to double check?

File: app/models/label.rb

Scope name "label_links" is right ?

Why was this MR needed?

It's better for user experience.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Tests
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #22680 (moved)

Marked the task Branch has no merge conflicts with master (if it does - rebase it please) as incomplete

Added 911 commits:

• 04060477...38978fa5 - 910 commits from branch gitlab-org:master
• 141bf992 - Limit autocomplete to currently selected items

Marked the task Branch has no merge conflicts with master (if it does - rebase it please) as completed

Added 1 commit:

• d738247a - Limit autocomplete to currently selected items

Marked the task All builds are passing as completed

Thanks @akramfares, I had a couple of notes!

Added ~164274 ~584040 labels

Reassigned to @akramfares

Added 516 commits:

• d738247a...146e0cbc - 515 commits from branch gitlab-org:master
• 1c77b5b0 - Limit autocomplete to currently selected items

Compare with previous version

Resolved all discussions

Milestone changed to %8.14

Added 372 commits:

• 1c77b5b0...3c5b9474 - 371 commits from branch gitlab-org:master
• d47f39c9 - Limit autocomplete to currently selected items

Compare with previous version

Resolved all discussions