Subscriber user can edit Contact Email field

If merchant had been saved with:
1. No Contact Email, then user can add contact email (field is displayed empty) and Send Invite button (on Reports view) is displayed and available for user to send merchant user activation email.
2. Contact Email, then user can change this email address, the previous email address (merchant user) is disabled, and a new merchant user is created, and Send Invite button is displayed and available for user to send merchant user activation email.
3. Contact Email, then user can remove this email address (leave blank), the previous email address (merchant user) is disabled, and the Send Invite button is not displayed.

USER can then click the Save button on the Contact Info page and save all elements on this page for both Merchant and Merchant user objects as appropriate.

Contact Email is updated on the Merchants List View More page per current Contact Email field entry.

Contact Email address must be unique within Subscriber realm (as it is already today in production)

Contact Name and Contact Phone will not change per current production implementation, i.e. they can be edited and saved.