net-shapers: implement delete support for NODE scope shaper

Leverage the previously introduced group operation to implement
the removal of NODE scope shaper, re-linking its leaves under the
the parent node before actually deleting the specified NODE scope
shaper.

Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/763d484b5b69e365acccfd8031b183c647a367a4.1728460186.git.pabeni@redhat.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>