Upstream fixes for GLTF parsers
- Change the logic that the glTF parser uses to determine if a mesh primitive has been defined with multiple sets of uv coordinates.
- Make the inclusion of metallic, normal, emmissive, and ambient occlusion maps no longer dependent on the presence of a base color map.
Upstreamed patch from TRI ref. https://github.com/RobotLocomotion/drake/issues/20874
/cc @SeanCurtis-TRI
Edited by Ryan Krattiger