i3-companion: tentative to register for battery update from PulseAudio

Unfortunately, I am unable to receive anything... Maybe the path not
existing when registering does not help.

bin/i3-companion

@@ -743,6 +743,15 @@ async def bluetooth_notifications(i3, event, path, interface, changed, invalid):
             and "Percentage" in args[1]
         ),
     ),
+    DBusSignal(
+        path="/org/pulseaudio",
+        interface="org.freedesktop.DBus.Properties",
+        member="PropertiesChanged",
+        signature="sa{sv}as",
+        onlyif=lambda args: (
+            args[0] == "org.bluez.BatteryProvider1" and "Percentage" in args[1]
+        ),
+    ),
 )
 @retry(2)
 @debounce(1)