remove legaldoc requirement on domain delete

[vohmar]

adding legaldoc to domain delete request must be optional even if legaldoc requirement is enabled in the registry. Current default behavior is to require adding legaldocs on domain registration, registrant change and domain delete.

PS: There are form level validations in registrar portal as well that need to take this into account. Alternatively we could also consider removing form level legaldoc validation from registrar portal all together if this is much easier in comparison to following system settings.