Copy, don't move uploaded avatar files

Closes #26158

See merge request !8396

Fix cross-project references copy to include the project reference

Closes #25890

See merge request !8232

Remove bottom border from Issuable titles

See merge request !8278

[ci skip]

Fix Gemfile.lock for the octokit update

See merge request !8414

MR https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8158 updated
the octokit Gem but did not include all the changes for Gemfile.lock.

Also added relevant specs and refactored to_references in a bunch of places to be more consistent.

rewrite the item.respond_to?(:x?) && item.x? to item.try(:x?)

See merge request !8409

Add tests to cycle analytics

See merge request !7727

API: extern_uid is a string

Closes #26227

See merge request !8404

Update octokit to 4.6.2

See merge request !8158

Increases pipeline graph drowdown width in order to prevent strange position on chrome on ubuntu

Closes #26218

See merge request !8399

Adds MR ID to changelog entry

Remove time zone information from assertion in timeago tooltips spec

Closes #26183

See merge request !8374

Enable HAML-LINT linters

Closes #22072

See merge request !8247