Shipping Labels: Validate that address name field is not empty

[rachelmcr]

Description

This PR adds local validation to check that the shipping address name field is not empty when creating shipping labels. If it is empty, it opens the Edit Address screen to prompt the user to enter a name.

This was fixed on develop and the fix is being introduced to release/7.1 based on beta testing feedback. (Internal ref: p5T066-2uU-p2#comment-9242)

FYI @jkmassel since this is targeting the 7.1 release.

Changes

• Adds a check for address.name.isEmpty before doing the remote address validation in ShippingLabelFormViewModel.
• Adds a unit test.

Before	After

Testing

1. Make sure your First name and Last name are empty in your WordPress.com account settings.
2. Make sure you have configured the WooCommerce WCShip plugin, and you have one or more payment methods set up in WP Admin under WooCommerce > Settings > Shipping > WooCommerce Shipping.
3. Launch the app.
4. If you are already logged in, log out and log in again (to make sure you don't have old account settings stored in the app).
5. Open an order detail that is eligible for the shipping label.
6. Tap the button "Create Shipping Label".
7. In the Ship from section, tap the "Continue" button.
8. Confirm that the Edit Address screen opens (with the "Name missing" validation error prompting you to enter a name).

Submitter Checklist

Update release notes:

• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[pmusolino]

thanks for moving the name validation on release 7.1