Examples: Clean up.

[Mugen87]

Related issue: -

Description

The PR makes sure that webgpu_* examples that only support WebGPU use WebGPU.isAvailable() to report a controlled error on WebGL 2 only browsers.

The PR also removes a debug log from GLSLNodeBuilder.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	336.27 78.29	336.27 78.29	+0 B +0 B
WebGPU	516.74 143.47	516.71 143.46	-33 B -10 B
WebGPU Nodes	516.2 143.37	516.17 143.36	-33 B -9 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	465.25 112.13	465.25 112.13	+0 B +0 B
WebGPU	588.75 159.64	588.71 159.63	-33 B -12 B
WebGPU Nodes	544.13 149.2	544.1 149.19	-33 B -10 B