[Backport release-24.11] pixelfed: 0.12.3 -> 0.12.4

[nixpkgs-ci]

Bot-based backport to release-24.11, triggered by a label in #371746.

• Before merging, ensure that this backport is acceptable for the release.
  • Even as a non-commiter, if you find that it is not acceptable, leave a comment.

[mweinelt]

 Verifying lock file contents can be installed on current platform.
 Your lock file does not contain a compatible set of packages. Please run composer update.

   Problem 1
     - laravel-notification-channels/expo is locked to version v2.0.0 and an update of this package was not requested.
     - laravel-notification-channels/expo v2.0.0 requires php ~8.3 -> your php version (8.2.28) does not satisfy that requirement.

[mweinelt]

Ran the nixos test on x86_64-linux.