Fix 9.2 conflicts for "Remove max select for multiple assignees"

• Encountered conflicts while picking !1918 (merged) onto 9-2-stable
• Please fix the conflicts and merge this into 9-2-stable

Output of git status after picking !1918 (merged)

On branch 9-2-stable-ee
Your branch is up-to-date with 'origin/9-2-stable-ee'.
You are currently cherry-picking commit cf25c7f.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:

        new file:   spec/javascripts/multiple_assignees/sidebar_spec.js

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)

        deleted by us:   app/views/shared/issuable/_sidebar_assignees.html.haml