LightsNode: Honor spotlight maps in cache key.

[Mugen87]

Fixed #30930.

Description

The existence of a spot light map must be honored in the dynamic light cache key which is computed per frame. Otherwise dynamic changes to a spot light like described in #30930 produce runtime errors.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	336.33 78.33	336.33 78.33	+0 B +0 B
WebGPU	545.64 151.26	545.72 151.3	+78 B +40 B
WebGPU Nodes	544.99 151.1	545.07 151.14	+78 B +40 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	465.48 112.23	465.48 112.23	+0 B +0 B
WebGPU	619.26 167.56	619.34 167.59	+78 B +35 B
WebGPU Nodes	574.13 156.86	574.21 156.89	+78 B +32 B