sysprof-power-profile: Use UPower DBus API

Since some time the power-profiles-daemon project has been moved under the upower umbrella and renamed its API to follow that.

While the legacy name is still supported, there are plans to not support it anymore in future [2]. So let's update gnome-shell code to use the current main name instead.

[1] https://gitlab.freedesktop.org/upower/power-profiles-daemon/-/merge_requests/148 [2] https://gitlab.freedesktop.org/upower/power-profiles-daemon/-/merge_requests/166