A clipping path hides the art outside it. Empty Text removed empty type
that clips a clipping group, and Off-Artboard Art removed type that clips
a layer from off every artboard, so the art they hid showed. Both now
leave type that is a clipping path, as the other kinds already did, also
when the clipping path itself is selected.
Docs: docs/mcp.md (Artwork Cleanup kinds table).