Make City and Postal code fields optional during Customers Portal registration

Problem

Customers Portal sign up form has City and Postal code fields as required fields. These fields are only truly required for the purposes of checkout, and now that we have the ability to capture address in the checkout, we can handle the requirement on checkout.

Proposal

We can look into either removing City and Postal code fields during sign up or mark them as optional fields.

⚠ Important: Before we can make this change, we will need to add address in Self-Managed, Community Programs and potentially Duo Pro checkout flows.