BatchedMesh: Add deleteGeometry().

[gkjohnson]

Related issue: #29463

Description

Adds a "deleteGeometry" function to BatchedMesh that follows the same patterns as #29449 - so if a geometry is removed it's id is reused, simplifying the implementation of future "optimize" function since ids won't have to be remapped.

cc @JordanLane-Veerum

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	687.15 170.18	687.47 170.27	+319 B +84 B
WebGPU	805.82 216.97	806.14 217.06	+319 B +92 B
WebGPU Nodes	805.33 216.83	805.64 216.92	+319 B +91 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	462.85 111.79	462.85 111.79	+0 B +0 B
WebGPU	535.59 144.55	535.59 144.55	+0 B +0 B
WebGPU Nodes	491.75 134.31	491.75 134.31	+0 B +0 B