cephadm: disable UDP in samples/nfs.json for test_cephadm Ganesha

cephadm: disable UDP in samples/nfs.json for test_cephadm Ganesha
test_cephadm.sh deploys NFS through cephadm _orch deploy using
src/cephadm/samples/nfs.json. That sample is separate from the mgr
ganesha.conf.j2 template, which already sets Enable_UDP = false.
Without that setting, Ganesha on Rocky 10 (ceph-ci image) fails during
startup with "Cannot register NFS V3 on UDP", so test_cephadm.sh never
sees ganesha.nfsd listening on port 2049.
Add Protocols = 3, 4 and Enable_UDP = false to NFS_CORE_PARAM so the
sample matches the orchestrator defaults.
Fixes: https://tracker.ceph.com/issues/76295
Signed-off-by: Kobi Ginon <kginon@redhat.com>