The import nodes are considered complete enough to expose without
the experimental option. This commit removes the option so they will
be exposed in 4.5. There are still some possible future improvements,
including automatic caching, possibly exposing more input sockets,
and possibly including imported paths in the "Internal Dependencies"
panel. Those are considered non blocking though.
Pull Request: https://projects.blender.org/blender/blender/pulls/135957
835696f152