NodeMaterial: Execute setupVertex() if vertexNode is defined

[sunag]

Fixes #31131

Description

Execute setupVertex() if vertexNode is defined which can be useful to reuse the vertex transformation by modifying the MVP.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	337.26 78.64	337.26 78.64	+0 B +0 B
WebGPU	550.2 152.54	550.2 152.54	+4 B +6 B
WebGPU Nodes	549.55 152.38	549.55 152.38	+4 B +6 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	468.12 113.14	468.12 113.14	+0 B +0 B
WebGPU	625.57 169.31	625.57 169.32	+4 B +8 B
WebGPU Nodes	580.42 158.62	580.42 158.63	+4 B +10 B