Update ClusteredMapView.js

Fix for 'region' undefined in '_onRegionChangeComplete'

Author: romain-spielmann

lib/ClusteredMapView.js

@@ -125,7 +125,7 @@ const ClusteredMapView = forwardRef(
     }, [isSpiderfier, markers]);
 
     const _onRegionChangeComplete = (region) => {
-      if (superCluster) {
+      if (superCluster && region) {
         const bBox = calculateBBox(region);
         const zoom = returnMapZoom(region, bBox, minZoom);
         const markers = superCluster.getClusters(bBox, zoom);