NodeMaterial: Added support to custom MRT depth

[sunag]

Related issue: #29106 (comment)

Description

Added support to custom MRT depth:

const scenePass = pass( scene, camera );

scenePass.setMRT( mrt( {
	output,
	depth: depth // change depth output pass if you want
} ) );

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
685.1 kB (169.6 kB)	685.1 kB (169.6 kB)	+0 B

🌳 Bundle size after tree-shaking

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

Filesize dev	Filesize PR	Diff
462 kB (111.4 kB)	462 kB (111.4 kB)	+0 B