Fixed slash commands not loading

What does this MR do?

Fixes an issue with slash commands not working when the autocomplete source is loading & then the new issue button is clicked. This also fixes an issue where the autocomplete source is loaded on pages where it isn't actually needed.

What are the relevant issue numbers?

Closes #21774 (closed), #21807 (closed)

Added 1 commit:

• f40e8385 - Correctly loads gfm autocomplete source on pages where it is required

Added 1 commit:

• f40e8385 - 1 commit from branch master

Added 27 commits:

• f40e8385...553180e1 - 25 commits from branch master
• 45c08dcd - Fixed slash commands not loading
• c54f53b2 - Correctly loads gfm autocomplete source on pages where it is required

Added 1 commit:

• b6b3d0d1 - CHANGELOG item

Added 1 commit:

• a085e092 - Correctly loads gfm autocomplete source on pages where it is required

Added 1 commit:

• 67546284 - Fixed group milestone error

Reassigned to @jschatz1

Added 1 commit:

• 96467d74 - Use admin user in tests

Added 69 commits:

• 96467d74...57c4036d - 65 commits from branch master
• 5a661dba - Fixed slash commands not loading
• a2ebd3ba - Correctly loads gfm autocomplete source on pages where it is required
• 7413d3bf - Fixed group milestone error
• 8799aed9 - Use admin user in tests

@iamphill I still see unresolved discussions. Still says one out of two discussions resolved. Resolve those and assign to me.

Reassigned to @iamphill

Resolved all discussions

Reassigned to @jschatz1

Added ~584040 label

Reassigned to @iamphill

Added 452 commits:

• 8799aed9...7ac47516 - 447 commits from branch master
• 3531032e - Fixed slash commands not loading
• a5035ed3 - Correctly loads gfm autocomplete source on pages where it is required
• cd9a2ba1 - Fixed group milestone error
• 9c5638fb - Use admin user in tests
• b66a8203 - Moved loading GFM source into zen.html.haml

Resolved all discussions

Reassigned to @jschatz1

Resolved all discussions

Added ~149423 label

@jschatz1 Going to steal this one from you, I think it's good to go.

Reassigned to @rspeicher

Status changed to merged

Mentioned in commit cbb9507c

Picked into 8-12-stable, will go into RC7.

Removed ~149423 label

Mentioned in commit c525ec9b

Mentioned in merge request !6569 (merged)

Mentioned in issue #22827 (closed)