`useKTX2` does not allow to use external loader instances

[davcri]

Problem description:

There is no way with useKTX2() to use an external loader instance like useGLTF (see https://drei.docs.pmnd.rs/loaders/gltf-use-gltf#extendloader).

I recently needed to use useGLTF() and useKTX2() at the same time and I got this warning coming from three-stdlib/loaders/KTX2Loader.js :

THREE.KTX2Loader: Multiple active KTX2 loaders may cause performance issues.

This warning means that some resources are downloaded twice and two web workers are spawned.

Minimal example

https://codesandbox.io/p/sandbox/confident-hypatia-vp4s7q