Resolve issue where optional shipping parameters were required

[jackellenberger]

• When shippingAddressRequired() was true, all sub paramsi erroneously also became required
• Allow users to require shipping address without requiring country codes or phone number

TODO

• [x] look for other instances where similar bugs may occur

@braintree/team-dx

[jackellenberger]

Look like billingAddressParameters does not have the same issue as a default is provided for both optional params.