Use nfsd update command for restart

[allisonlarson]

Updates the nfs_restart_command for darwin hosts to use update instead of restart, after mac Sonoma update. Also adjusts the nfs mount log to run within the block, so it can access the opts hash.

fixes #13364

[chrisroberts]

Since the nfs_restart_command capability is defined, and the export wants to just do an update, it would be better to add a new nfs_update_command capability here and then update the nfs_export to call that.

[chrisroberts]

This looks great!