Fix neraby leak B, leak caused map marker's have reference to activity stays remain on destroy fragment

Author: neslihanturan

app/src/main/java/fr/free/nrw/commons/nearby/NearbyMapFragment.java

@@ -821,6 +821,9 @@ public void onDestroyView() {
         if (mapView != null) {
             mapView.onDestroy();
         }
+        selected = null;
+        currentLocationMarker = null;
+
         super.onDestroyView();
     }