Brightness control doesn't work with mutter-49+

[garaevdi]

What Happened?

Since gnome 49 gnome-settings-daemon's dbus interface for managing backlight was removed. If I understood correctly, now gnome-shell directly "asks" mutter to change it using new Meta.Backlight class. Perhaps gala can implement its own dbus interface for managing screen brightness?

Relevant MRs:
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4014
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3715

Steps to Reproduce

1. Try to change brightness when running gala with mutter 49+
2. Nothing happens

Expected Behavior

Screen brightness changing

OS Version

Other Linux

OS Architecture

amd64 (on most hardwares)

Session Type

Secure Session (Wayland, This is the default)

Software Version

Latest release (I have run all updates)

Log Output

Hardware Info

No response