TSL: Improve warnings (2)

[sunag]

Related issue: #30849

Description

Improves checks to prevent the renderer from freezing if the code has issues.
TSL normally replaces the faulty node with an "identity" value, regardless of the expected type.

Returning null value from a Fn()

material.colorNode = Fn( () => { } )();

Now

Old

Return snippet verification for all nodes

material.colorNode = vec3( Fn( () => { } )() );

Now

Old

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	338.62 79.03	338.62 79.03	+0 B +0 B
WebGPU	566.43 156.57	566.96 156.76	+530 B +189 B
WebGPU Nodes	565.03 156.32	565.56 156.51	+530 B +189 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	470.05 113.73	470.05 113.73	+0 B +0 B
WebGPU	637.91 172.58	638.44 172.77	+530 B +189 B
WebGPU Nodes	592.56 161.85	593.09 162.03	+530 B +184 B