WebGPUAttributeUtils: Add int8/uint8 patch

[sunag]

Related issue: #30264

Description

Add int8/uint8 patches

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	336.02 78.26	336.02 78.26	+0 B +0 B
WebGPU	525.07 146.25	525.13 146.26	+57 B +9 B
WebGPU Nodes	524.53 146.15	524.59 146.16	+57 B +9 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	465.06 112.14	465.06 112.14	+0 B +0 B
WebGPU	597.85 162.51	597.9 162.52	+57 B +9 B
WebGPU Nodes	552.97 152	553.03 152	+57 B +10 B