Fix "invalid phone number' error on Uber Direct integration.#987

We are using the Uber Direct integration for all deliveries in New Zealand. About 1/100 delivery orders is allowed to be placed despite a phone number being entered which the system deems to be invalid. This seems to be caused by at least three situations.

1. The phone number is actually invalid
2. The system decides it is invalid when it is not
3. The phone number is formatted in a way that is deemed to be invalid but it is a real phone number.

There are a couple of simple changes which could solve these issues:
Make the checkout page display “Mobile Phone Number” instead of “Phone Number” and include a prefix selector for valid numbers. NZ cell phone prefixes are; 020, 021, 022 & 027.

Further, when someone does enter the wrong number and is still allowed to progress to complete their order, there is no way to edit their phone number from the admin dashboard. The only way to correct it right now and complete the delivery is to replace an order for the customer, requiring an additional payment through Stripe to process the order. If you could add a way to edit the phone number in the existing order, staff could more easily fix issues and get the delivery driver scheduled quickly.