Fix: prevent event loop error in ROGCC

Leftover code from parts of the refactor and tray crate change were
causing the app to crash due to the UI trying to issue a command on the
slint thread when the slint thread had not been created yet.

Closes #579

asusd/src/aura_manager.rs

@@ -268,7 +268,7 @@ impl DeviceManager {
                     found.push(path);
                 }
             } else {
-                warn!("No serial for SCSI device");
+                debug!("No serial for SCSI device: {:?}", device.devpath());
             }
         }