[google_maps_flutter] Improve widget build performance

The widget build was serializing the widget parameters each frame even though in the useAndroidSurface case they were only being used for creation (updates being done through didUpdateWidget). Use late initialization to skip serialization if not needed.

packages/google_maps_flutter/google_maps_flutter_android/lib/src/google_maps_flutter_android.dart

@@ -570,7 +570,7 @@ class GoogleMapsFlutterAndroid extends GoogleMapsFlutterPlatform {
     MapObjects mapObjects = const MapObjects(),
     Map<String, dynamic> mapOptions = const <String, dynamic>{},
   }) {
-    final Map<String, dynamic> creationParams = <String, dynamic>{
+    late final Map<String, dynamic> creationParams = <String, dynamic>{
       'initialCameraPosition':
           widgetConfiguration.initialCameraPosition.toMap(),
       'options': mapOptions,