SpriteNodeMaterial: Fix scaleNode type convertion

[sunag]

Fixes: #30539

Description

Fix scaleNode type convertion of SpriteNodeMaterial.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	336.36 78.33	336.36 78.33	+0 B +0 B
WebGPU	518.85 144	518.85 144	+0 B +1 B
WebGPU Nodes	518.32 143.88	518.32 143.88	+0 B +1 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	465.35 112.17	465.35 112.17	+0 B +0 B
WebGPU	590.68 159.95	590.68 159.95	+0 B +2 B
WebGPU Nodes	545.99 149.43	545.99 149.43	+0 B +0 B