[suspend][core] [1.x] fix: suspended users can remove avatar

[imorland]

Reported https://discuss.flarum.org/d/32899-flarum-v180-released/83 and following on from #3890

Changes proposed in this pull request:
Dispatch AvatarDeleting before beginning the avatar deletion process, add a listener to flarum/suspend to prevent a suspended user from removing their avatar. Admins and other users with permission may still remove the avatar of the suspended user if required.

New tests for this scenario are included. Happy to make the same change against the 2.x branch if required, please let me know.

Reviewers should focus on:

Screenshot

QA

Necessity

• Has the problem that is being solved here been clearly explained?
• If applicable, have various options for solving this problem been considered?
• For core PRs, does this need to be in core, or could it be in an extension?
• Are we willing to maintain this for years / potentially forever?

Confirmed

• Frontend changes: tested on a local Flarum installation.
• Backend changes: tests are green (run composer test).
• Core developer confirmed locally this works as intended.
• Tests have been added, or are not appropriate here.

[imorland]

Ugh, damn StyleCI. See f7c0a3b for my changes here.

[luceos]

Can you please do the reformatting as a direct commit to main/master and then apply the change for the subject as a or?

Thanks.

Did not see the comment about StyleCI, my bad.

[luceos]

I am a bit confused. It seems the abuse prevention @SychO9 implemented with https://github.com/flarum/framework/pull/3890/files#diff-d6304eb2471ddda50b8b56050c4e6ed1f6f0ac4b2511af0de4f363cddeca3bf8 uses the Gate. Why can't we either a) implement another policy ability for avatar removal or b) rename the implemented one to avatar changing. The intention of both PR's seem very similar, yet the implementations are entirely different with one using a Gate and the other Events.

[imorland]

I agree that what you're saying would make sense for 2.x, but I feel that if that was implemented in 1.x we run the risk of introducing a breaking change by adding a removeAvatar gate.

How would we feel about the change proposed here for 1.x as a "quick fix/patchup", and a solution based on a gate for 2.x?