NodeUtils: Replace instanceof Array with Array.isArray().

[Mridul012]

Summary

Replaces instanceof Array with Array.isArray for more robust array checking.

Impact

Array.isArray is the recommended approach and works correctly across different execution contexts. No functional change intended.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	360.01 85.46	360.01 85.46	+0 B +0 B
WebGPU	633.38 175.63	633.38 175.63	-2 B -3 B
WebGPU Nodes	631.5 175.34	631.5 175.34	-2 B -3 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	492.21 120.03	492.21 120.03	+0 B +0 B
WebGPU	705.41 190.51	705.41 190.51	-2 B -1 B
WebGPU Nodes	654.63 177.77	654.63 177.77	-2 B +0 B