python313Packages.pillow-heif: disable failing test

Pillow since 11.2.0 comes with AVIF support, but apparently something is
wrong with its EXIF support.

pkgs/development/python-modules/pillow-heif/default.nix

···
     [
       # Time based
       "test_decode_threads"
+      # Missing EXIF info on WEBP-AVIF variant
+      "test_exif_from_pillow"
     ]
     ++ lib.optionals stdenv.hostPlatform.isDarwin [
       # https://github.com/bigcat88/pillow_heif/issues/89