paste object with a mesh to a different file fails to copy the mesh
#### Steps to reproduce:
- draw a shape and apply a mesh;
- copy the shape;
- open a new file and paste the shape;
#### What happened?
- only the shape is pasted without any color.
Same happens when cut and paste to a different file.
#### What should have happened?
- I would expect a copy of the object with the mesh.
#### Inkscape Version and Operating System:
- Inkscape 1.0rc1 (cb074a3, 2020-04-24) - I believe I had this issue before too.
- Linux 64 Debian testing
- Gnome 3.36.1
issue