SplitNode: Fix unecessary swizzle (#24170)
SplitNode: Fix unecessary swizzle (#24170)

* SplitNode: Fix unecessary swizzle

* replace .substr() to .slice()
aardgoose/three.js,aardgoose/three.js,06wj/three.js,makc/three.js.fork,mrdoob/three.js,gero3/three.js,WestLangley/three.js,gero3/three.js,WestLangley/three.js,06wj/three.js,makc/three.js.fork,mrdoob/three.js