Copy custom data and flag from the original edge to the ones created
from it when splitting a long edge.
Unfortunately, can not use generic "example" edge approach as there
is a temporary flag BM_ELEM_TAG is re-applied in a loop: the new
edges can not be tagged with this tag. Additional complication is
that even we clear this tag from the input edge before splitting it
this tag is re=applied via long_edge_queue_face_add().
Hence, use our own simple function to copy minimal subset of data and
tags.
Co-Authored-By: Hans Goudey <hans@blender.org>
Pull Request: https://projects.blender.org/blender/blender/pulls/113783
f8ee27c88b