In `execute_realize_grease_pencil_tasks` we create a new `GreasePencil`
but don't copy the parameters of (one of) the source grease pencils.
The fix adds `BKE_grease_pencil_copy_parameters` to copy the parameters
of the last src grease pencil.
Note: `BKE_grease_pencil_copy_parameters` copies the materials array. We
might want to remove this and always do the copy of this using a separate
function because some callers need their own way of copying them.
Pull Request: https://projects.blender.org/blender/blender/pulls/129977
761f075f8d