add stopAnimationByName

lib/filament_controller.dart

@@ -365,7 +365,9 @@ abstract class FilamentController {
 
   Future setAnimationFrame(
       FilamentEntity entity, int index, int animationFrame);
+
   Future stopAnimation(FilamentEntity entity, int animationIndex);
+  Future stopAnimationByName(FilamentEntity entity, String name);
 
   ///
   /// Sets the current scene camera to the glTF camera under [name] in [entity].

lib/filament_controller_ffi.dart

@@ -950,6 +950,12 @@ class FilamentControllerFFI extends FilamentController {
         _sceneManager!, entity, index, loop, reverse, replaceActive, crossfade);
   }
 
+  @override
+  Future stopAnimationByName(FilamentEntity entity, String name) async {
+    var animations = await getAnimationNames(entity);
+    await stopAnimation(entity, animations.indexOf(name));
+  }
+
   @override
   Future playAnimationByName(FilamentEntity entity, String name,
       {bool loop = false,