Better support for resetting avatar/header/background
Currently you can't remove/reset the profile images through update_credentials, but instead there's new custom pleroma api endpoints (/api/v1/pleroma/accounts/update_avatar
etc) for resetting each individual images. however that api is pretty ugly and poorly documented. for whatever reason those endpoints don't return useful data (would expect an account), and their parameters seem pretty wild (avatar takes 'img', banner takes 'banner' and background takes 'img' again). I wouldn't want to make use of that api as once it's in use it'll be harder to rip out or fix.
I talked with lain about it and figured maybe it'd be a better idea to allow giving empty strings in the forms to mastoapi PATCH update_credentials for avatar/header etc and have it reset the image that way. currently we return 200 OK but don't do anything if you give null in json for avatar/header/background, and error when you try giving null to the form (which is always supposed to be used for files according to masto docs) but empty string in forms 200 OK with no effect again. there was some concern that null in json might be sent by some applications expecting it not to have side effects, so maybe empty string is safer in that regard.
more discussion on the FE MR about this stuff: pleroma-fe!1156 (merged)