auto_recalculate doesn't trigger if phone number changed

Problem/Motivation

If you have auto_recalculate enabled, have the phone number showing on the form and use custom logic to validate the phone number, e.g. make it required for certain countries, if you trigger the validation logic to initially fail the form doesn't re-submit via AJAX and re-validate the field, thus shipping options won't be shown via AJAX.

Steps to reproduce

Enable auto_recalculate.
Enable the phone number on the order profile address.
Add custom validation logic on the phone number field that causes it to fail under certain circumstances.
Add an item to the cart.
Load the checkout form.
Fill in all required fields on the address, but don't fill in the phone number field in a way that causes it to fail validation.
Will see this:
1. The form will show an error via AJAX per the validation failure.
2. No shipping options will be shown.
Fill in the phone number field, tab to another field.

Expected results:
1. The shipping information re-validates via AJAX.
2. The phone number field passes validation.
3. Shipping options are displayed.

Actual results:
1. The shipping information doesn't re-validate.

Proposed resolution

The shipping information's address re-validates when the phone number field is changed.

Remaining tasks

Work out the best approach to this.

User interface changes

The checkout shipping information's address re-validates when the phone number field is changed.

API changes

TBD

Data model changes

TBD