use AppState to get device roles

i _understand_ now!
basically, i did it the "wrong" way first by modifying openxr.rs and openvr.rs to pass battery levels to osc, when really i could have just made osc get the pre-formatted device details from AppState. live and learn, i'm new to rust anyway.

src/backend/openvr/mod.rs

@@ -324,7 +324,7 @@ pub fn openvr_run(running: Arc<AtomicBool>, show_by_default: bool) -> Result<(),
 
         #[cfg(feature = "osc")]
         if let Some(ref mut sender) = osc_sender {
-            let _ = sender.send_params(&overlays);
+            let _ = sender.send_params(&overlays, &state); // i love inconsistent naming; in openxr.rs `state` is called `app_state`
         };
 
         #[cfg(feature = "wayvr")]