DRACOLoader: Add exported urls for GLTF decoder

[gkjohnson]

Related issue: #33564 (comment), #33602

Description

This PR updates DRACOLoader to support passing an object into "setDecoderPath" that specifies both the "js" and "wasm" file paths, and additionally provides an export of a pre-formed paths object for pointing to the in-project gltf decoder files:

import { DRACOLoader, DRACO_GLTF_CONFIG } from 'three/addons/loaders/DRACOLoader.js;

// takes a string OR an object
const loader = new DRACOLoader().setDecoderPath( {
  js: './path/to/decoder.js',
  wasm: './path/to/decoder.wasm',
} );

// or use the provided config
const loader = new DRACOLoader().setDecoderPath( DRACO_GLTF_CONFIG );

• Exporting the urls like this allows the bundlers to resolve the urls correctly so they can be used by users.
• This will enable these urls to be tree-shaken by bundlers.
• Using "setDecoderPath" rather than something like a "useGltfVariant" flag avoids conceptual conflicts between the two (eg what does it mean if a user has explicitly set the decoder paths but also set "useGltfVariant" to true?)
• It might be worth considering a different function name for this? Or a separate function entirely?
• Updates 1 example to demonstrate functionality. I will submit a subsequent PR updating the remaining examples if this is accepted.

[gkjohnson]

Okay merging this! There's some working happening on a "tinydraco" WASM bundle so we may be able to converge on one WASM bundle sooner rather than later if everything works out and this proves to be reliable:

https://x.com/boulabiar/status/2062257485491110112