Derives timestamp buffer size from BigUint64Array instead of BigInt64Array

[ycw]

Timestamp query will resolve as u64, not i64, so the code should reflect this fact even if the BYTE_PER_ELEMENT has no difference between them

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	339.51 79.09	339.51 79.09	+0 B +0 B
WebGPU	490.94 136.34	490.94 136.33	+1 B -5 B
WebGPU Nodes	490.41 136.22	490.41 136.22	+1 B -4 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	465.35 112.14	465.35 112.14	+0 B +0 B
WebGPU	560.24 151.74	560.24 151.74	+1 B -3 B
WebGPU Nodes	516.33 141.53	516.33 141.52	+1 B -2 B