TSL: Fix lightShadowMatrix() if renderer.shadowMap.enabled is false

[sunag]

Related issue: #31022

Description

Fix lightShadowMatrix() if renderer.shadowMap.enabled is false.

[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	547.81 151.89	547.85 151.9	+34 B +15 B
WebGPU Nodes	547.16 151.73	547.2 151.74	+34 B +15 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	465.78 112.28	465.78 112.28	+0 B +0 B
WebGPU	622.7 168.46	622.73 168.47	+34 B +12 B
WebGPU Nodes	577.57 157.72	577.6 157.74	+34 B +12 B