use generic parameter in FilamentApp for renderableManager/transformManager/etc, and only expose as getters in the interface

thermion_dart/lib/src/filament/src/implementation/ffi_filament_app.dart

@@ -53,15 +53,7 @@ class FFIFilamentApp extends FilamentApp<Pointer> {
       this.ubershaderMaterialProvider,
       this.renderTicker,
       this.nameComponentManager,
-      Future<Uint8List> Function(String uri)? loadResource)
+      Future<Uint8List> Function(String uri)? loadResource) {
-      : super(
-            engine: engine,
-            gltfAssetLoader: gltfAssetLoader,
-            renderer: renderer,
-            transformManager: transformManager,
-            lightManager: lightManager,
-            renderableManager: renderableManager,
-            ubershaderMaterialProvider: ubershaderMaterialProvider) {
     this._loadResource = loadResource ?? defaultResourceLoader;
   }
 

thermion_dart/lib/src/filament/src/interface/filament_app.dart

@@ -28,22 +28,13 @@ class FilamentConfig<T, U> {
 abstract class FilamentApp<T> {
   static FilamentApp? instance;
 
-  final T engine;
+  T get engine;
-  final T gltfAssetLoader;
+  T get gltfAssetLoader;
-  final T renderer;
+  T get renderer;
-  final T transformManager;
+  T get transformManager;
-  final T lightManager;
+  T get lightManager;
-  final T renderableManager;
+  T get renderableManager;
-  final T ubershaderMaterialProvider;
+  T get ubershaderMaterialProvider;
-
-  FilamentApp(
-      {required this.engine,
-      required this.gltfAssetLoader,
-      required this.renderer,
-      required this.transformManager,
-      required this.lightManager,
-      required this.renderableManager,
-      required this.ubershaderMaterialProvider});
 
   ///
   ///
@@ -369,4 +360,6 @@ abstract class FilamentApp<T> {
   /// [setSkybox] is called.
   ///
   Future<Skybox> buildSkybox({Texture? texture = null});
+
+
 }