-Make sure monitorable cant be flipped while flushing queries, fixes #17330

-Also added set_deferred, this was missing.

servers/physics/physics_server_sw.h

@@ -51,6 +51,8 @@ class PhysicsServerSW : public PhysicsServer {
 	int active_objects;
 	int collision_pairs;
 
+	bool flushing_queries;
+
 	StepSW *stepper;
 	Set<const SpaceSW *> active_spaces;
 
@@ -365,6 +367,8 @@ public:
 	virtual void flush_queries();
 	virtual void finish();
 
+	virtual bool is_flushing_queries() const { return flushing_queries; }
+
 	int get_process_info(ProcessInfo p_info);
 
 	PhysicsServerSW();