Revert: Require postcode on create + update

This reverts commit dd9b4e8a8262f2ddd6ea7ecd2c85a44141ab41e4.

This fixes password reset when user enters a new password
Validations are firing preventing users from saving new password
Merge pull request #813 from moneyadviceservice/revert-user-validation

Revert: Require postcode on create + update