isisd: Allow full `no` form for `domain-password` and `area-password`

isisd: Allow full `no` form for `domain-password` and `area-password`

Before:

```
LR1.wue3(config)# router isis VyOS
LR1.wue3(config-router)# no  area-password clear
% Unknown command: no  area-password clear
LR1.wue3(config-router)# no  area-password clear foo
% Unknown command: no  area-password clear foo
LR1.wue3(config-router)#
```

Closes https://github.com/FRRouting/frr/issues/17722

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
(cherry picked from commit a696547d6c78d4140649f96d6bef9a335fe5dfa5)