Extension of the WebGPU copyTextureToTexture function for array textures

[Spiri0]

So far you can only use the copyTextureToTexture function to copy from one simple texture to another simple texture. But it is also desirable to be able to copy from a simple texture to an array texture and vice versa. That's why I expanded the function a little bit to make this possible. I tested that straight away too. In my app I had no impact on the existing code, but I can now copy textures into array textures. The 1 in line 1450 means that only one layer should be copied.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	685.24 169.64	685.24 169.64	+0 B +0 B
WebGPU	826.2 221.55	826.23 221.58	+28 B +25 B
WebGPU Nodes	825.78 221.46	825.81 221.49	+28 B +25 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	462.02 111.48	462.02 111.48	+0 B +0 B
WebGPU	525.3 141.56	525.32 141.58	+28 B +24 B
WebGPU Nodes	481.95 131.37	481.98 131.39	+28 B +25 B