URP プロジェクトで matcap を含むモデルを Editor import するとエラーになるのを回避(暫定)

とりえあずエラー回避。
`Exception: UnityEngine.Texture.Sphere is not converted`
mtoon URP "MToon" shader is not ready. import fallback to unlit

Assets/UniGLTF/Editor/UniGLTF/ScriptedImporter/TextureExtractor.cs

@@ -59,7 +59,8 @@ public void Extract(SubAssetKey key, TextureDescriptor texDesc)
             }
             else
             {
-                throw new Exception($"{key} is not converted.");
+                // throw new Exception($"{key} is not converted.");
+                Debug.LogWarning($"{key} is not converted.");
             }
         }