When creating a texture view, Metal may require that the original
GPUTexture state is modified in some way. This may be a result
of deferred creation, or, to cache the texture view against the
source.
As a result, GPUTexture passed into GPU_texture_create_view
cannot be const.
Small fixes have also been made in the Metal texture
implementation to ensure correct function of texture views.
Authored by Apple: Michael Parkin-White
Ref #96261
