LightsNode: Honor map version in cache key.

[Mugen87]

Related issue: #31330

Description

The custom cache key of LightsNode must honor the version of spot light maps otherwise a texture update is not correctly honored. webgpu_lights_projector only worked since the material observer forces a refresh for each new renderId. But if you add more than one objects that share a node builder state (and thus material observer) and are affected by the spot light, textured lighting breaks for all objects except the first one.

Note: The video texture also works now but there are still WebGPU warnings in the console:

External texture [ExternalTexture (unlabeled)] used in a submit is not active.
Destroyed texture [Texture "IOSurface(Gles2Read|RasterRead|DisplayRead|Scanout|WebgpuRead)"] used in a submit.

WebGL reports no warnings. Investigating this separately.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	338.27 78.93	338.27 78.93	+0 B +0 B
WebGPU	558.51 154.58	558.54 154.59	+34 B +9 B
WebGPU Nodes	557.43 154.36	557.46 154.37	+34 B +9 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	469.62 113.66	469.62 113.66	+0 B +0 B
WebGPU	634.14 171.61	634.18 171.62	+34 B +7 B
WebGPU Nodes	589.28 160.95	589.31 160.95	+34 B +7 B

[ycw]

It'd rebuild nodes for each video texture update, in turns huge frames drop

[Mugen87]

Indeed, the refresh isn't performant yet for video textures combined with SpotLight.map. We must track somehow the version to trigger a bindings update though.

[ycw]

That's what I tried to achieve at #31369 but in sloppy way...