api: ceph: mds: do not set unused keys in config file

... during MDS creation.

The configuration keys:
- mds_standby_for_name
- mds_standby_replay

Were removed for Ceph 14.1.1 in [1].

[1] https://github.com/ceph/ceph/commit/d4638836ba2335f5b8eeb4a7624992caf7bb6901

Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
Link: https://lore.proxmox.com/all/20260715082434.116441-3-m.sandoval@proxmox.com