Fix rotation gizmo for empty Spatials

The AABB for an empty Spatial has 0 size, since the stored and
compared Transform was scaled by the AABB size, it would completely
destroy the rotation information. If there is no rotation
information, the gizmo doesn't update when the rotation changes.

(cherry picked from commit a0af3094b47fabb1fd6bb7f5e5aecc8fefd2486c)

editor/plugins/spatial_editor_plugin.cpp

@@ -2389,11 +2389,18 @@ void SpatialEditorViewport::_notification(int p_what) {
 			if (!se)
 				continue;
 
+			Transform t = sp->get_global_gizmo_transform();
+
+			exist = true;
+			if (se->last_xform == t)
+				continue;
+			changed = true;
+			se->last_xform = t;
+
 			VisualInstance *vi = Object::cast_to<VisualInstance>(sp);
 
 			se->aabb = vi ? vi->get_aabb() : _calculate_spatial_bounds(sp);
 
-			Transform t = sp->get_global_gizmo_transform();
 			t.translate(se->aabb.position);
 
 			// apply AABB scaling before item's global transform
@@ -2401,11 +2408,6 @@ void SpatialEditorViewport::_notification(int p_what) {
 			aabb_s.scale(se->aabb.size);
 			t.basis = t.basis * aabb_s;
 
-			exist = true;
-			if (se->last_xform == t)
-				continue;
-			changed = true;
-			se->last_xform = t;
 			VisualServer::get_singleton()->instance_set_transform(se->sbox_instance, t);
 		}