Sampling UV1 on a Nanite mesh with one UV channel returns a constant value

This is general for any UV channel past what the static mesh has, rather than specifically for UV channel 1.

1. Download attached repo project, open
2. Observe the two planes. The material uses UV channel 2 (as both planes have
   channels 0 and 1).
   1. The plane not set to Nanite uses UV channel 1 as a fallback.
   2. The Nanite plane uses a constant as a fallback