fix pcvr

crates/bevy_openxr/src/openxr/action_set_attaching.rs

@@ -14,6 +14,7 @@ impl Plugin for OxrActionAttachingPlugin {
 
 fn attach_sets(session: Res<OxrSession>, mut events: EventReader<OxrAttachActionSet>) {
     let sets = events.read().map(|v| &v.0).collect::<Vec<_>>();
+    if sets.is_empty() {return;}
     info!("attaching {} sessions", sets.len());
     match session.attach_action_sets(&sets) {
         Ok(_) => {info!("attached sessions!")}