WebGLRenderer: Fix WebXR Depth Sensing.

[cabanier]

The introduction of ExternalTexture broke support for WebXR Depth Sensing because the depth texture was never bound to the sampler.
Fixed by doing the same thing in setTexture2DArray as we do for setTexture2D.

cc @Mugen87

This contribution is funded by Meta

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	338.17 79.12	338.24 79.14	+79 B +15 B
WebGPU	579.39 160.1	579.39 160.1	+0 B +0 B
WebGPU Nodes	578 159.86	578 159.86	+0 B +0 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	469.76 113.82	469.83 113.84	+79 B +13 B
WebGPU	649.09 175.75	649.09 175.75	+0 B +0 B
WebGPU Nodes	603.2 164.92	603.2 164.92	+0 B +0 B

[cabanier]

This is broken in v179 and v180