WebGPURenderer: Improve checks for uniform buffer limits

[sunag]

Related issue: #30725 (comment)

Description

Improve checks for uniform buffer limits.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	359.21 85.29	359.21 85.29	+0 B +0 B
WebGPU	618.52 172.18	618.76 172.26	+243 B +88 B
WebGPU Nodes	617.1 171.93	617.34 172.01	+243 B +88 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	490.85 119.64	490.85 119.64	+0 B +0 B
WebGPU	692.34 187.32	692.56 187.4	+218 B +71 B
WebGPU Nodes	641.6 174.71	641.82 174.78	+218 B +72 B