NodeMaterialObserver: Add checking the lights

[sunag]

Fixes #31430
Related issue: #31396, #31330

Description

This reverts the cache PR, which can be useful if the texture is in a different format and the shader needs to be rebuilt. It also only checks the light for SpotLight that have the .map.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	338.02 78.86	338.02 78.86	+0 B +0 B
WebGPU	558.57 154.64	559.01 154.76	+444 B +118 B
WebGPU Nodes	557.49 154.42	557.93 154.54	+444 B +119 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	469.28 113.56	469.28 113.56	+0 B +0 B
WebGPU	633.86 171.66	634.3 171.8	+444 B +133 B
WebGPU Nodes	588.99 160.99	589.44 161.12	+444 B +123 B

[ycw]

thanks.