session/logind: Clean up add_signal_matches
session/logind: Clean up add_signal_matches

The original signal matching was using the old interface before
sd_bus_match_signal was added, which the new code uses.
Change them all to use it now.

ascent12/wlroots,swaywm/wlroots,ascent12/wlroots,swaywm/wlroots,SirCmpwn/wlroots