Fixed crash for Android API level below 18 on isFromMockProvider (react-native-maps#2172)

* Add Mock Provider boolean on each location update

* Update mapview.md

Update docs to specify that coordinate includes mock provider boolean

* Check API is 18 or above for isFromMockProvider

* Update docs to mention API

Author: chaitanyadeorukhkar

docs/mapview.md

@@ -49,7 +49,7 @@ To access event data, you will need to use `e.nativeEvent`. For example, `onPres
 | `onKmlReady` | `KmlContainer` | Callback that is called once the kml is fully loaded.
 | `onRegionChange` | `Region` | Callback that is called continuously when the region changes, such as when a user is dragging the map.
 | `onRegionChangeComplete` | `Region` | Callback that is called once when the region changes, such as when the user is done moving the map.
-| `onUserLocationChange` | `{ coordinate: LatLng }` | Callback that is called when the underlying map figures our users current location (coordinate also includes isFromMockProvider value for Android). Make sure **showsUserLocation** is set to *true* and that the provider is `"google"`.
+| `onUserLocationChange` | `{ coordinate: LatLng }` | Callback that is called when the underlying map figures our users current location (coordinate also includes isFromMockProvider value for Android API 18 and above). Make sure **showsUserLocation** is set to *true* and that the provider is `"google"`.
 | `onPress` | `{ coordinate: LatLng, position: Point }` | Callback that is called when user taps on the map.
 | `onPanDrag` | `{ coordinate: LatLng, position: Point }` | Callback that is called when user presses and drags the map. **NOTE**: for iOS `scrollEnabled` should be set to false to trigger the event
 | `onPoiClick` | `{ coordinate: LatLng, position: Point, placeId: string, name: string }` | Callback that is called when user click on a POI.

lib/android/src/main/java/com/airbnb/android/react/maps/AirMapView.java

@@ -196,8 +196,10 @@ public void onMyLocationChange(Location location){
         coordinate.putDouble("altitude", location.getAltitude());
         coordinate.putDouble("accuracy", location.getAccuracy());
         coordinate.putDouble("speed", location.getSpeed());
+        if(android.os.Build.VERSION.SDK_INT >= 18){
         coordinate.putBoolean("isFromMockProvider", location.isFromMockProvider());
-         
+        }         
+
         event.putMap("coordinate", coordinate);
 
         manager.pushEvent(context, view, "onUserLocationChange", event);