Improve integration with Live2D assets

- Added container-independent method for searching AnimationClip assets
(However, it's not really universal, so it can't completely replace the container-dependent method)

AssetStudioCLI/Options/CLIOptions.cs

@@ -586,6 +586,7 @@ namespace AssetStudioCLI.Options
                         o_exportAssetTypes.Value = new List<ClassIDType>
                         {
                             ClassIDType.AnimationClip,
+                            ClassIDType.Animator,
                             ClassIDType.MonoBehaviour,
                             ClassIDType.Texture2D,
                         };