Pull request #109518 (commit cf5666345d) added logic to rename the
active UV map to "st". However, this behavior is currently breaking
UV Map node export to USD Preview Surface materials.
Specifically, UV Map nodes that reference the original active map name
do not get updated to use the new name "st", and the exported USD shader
references an invalid texture coordinate primvar.
This commit removes this logic for now. We should support such
renaming in the future, but the behavior should be extended to update
the relevant UV Map nodes with the new name. Also, we should consider
adding a USD export option to enable this feature.
Pull Request: https://projects.blender.org/blender/blender/pulls/112234
678b827605