Allow Flatpak to communicate with MPRIS

See issue described on sonicnext-dev/MarathonRecomp#92 and sonicnext-dev/MarathonRecomp#125

Author: dakrk

flatpak/io.github.hedge_dev.unleashedrecomp.json

@@ -10,6 +10,7 @@
     "--socket=fallback-x11",
     "--socket=pulseaudio",
     "--device=all",
+    "--talk-name=org.mpris.MediaPlayer2.*",
     "--filesystem=host",
     "--filesystem=/media",
     "--filesystem=/run/media",