Fix multiple current location marker issue (commons-app#3243)

Author: neslihanturan

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

@@ -315,6 +315,7 @@ public void updateMapToTrackPosition(LatLng curLatLng) {
      */
     @Override
     public void addCurrentLocationMarker(LatLng curLatLng) {
+        removeCurrentLocationMarker();
         Timber.d("Adds current location marker");
 
         Icon icon = IconFactory.getInstance(getContext()).fromResource(R.drawable.current_location_marker);
@@ -336,8 +337,10 @@ public void addCurrentLocationMarker(LatLng curLatLng) {
 
     @Override
     public void removeCurrentLocationMarker() {
-        mapboxMap.removeMarker(currentLocationMarker);
-        mapboxMap.removePolygon(currentLocationPolygon);
+        if (currentLocationMarker != null) {
+            mapboxMap.removeMarker(currentLocationMarker);
+            mapboxMap.removePolygon(currentLocationPolygon);
+        }
     }
 
     /**

app/src/main/java/fr/free/nrw/commons/nearby/fragments/NearbyParentFragment.java

@@ -842,7 +842,6 @@ public void enableFABRecenter() {
 
     @Override
     public void recenterMap(fr.free.nrw.commons.location.LatLng curLatLng) {
-        nearbyMapFragment.removeCurrentLocationMarker();
         nearbyMapFragment.addCurrentLocationMarker(curLatLng);
         CameraPosition position;