#7041127 Checkout: Update Titan and Google Workspace descriptions to be more consistent

This pull request updates the Your order section of the checkout in order to show consistent information for all our email solutions: i.e. Professional Email, G Suite, and Google Workspace. The goal is to show the list of mailboxes for new accounts and additional mailboxes, and the number of mailboxes for renewals. This pull request also makes sure we display the product type:

New accounts

Before	After

Additional mailboxes

Before	After

Renewals

Before	After

Testing instructions

1. Run git checkout update/checkout-for-emails and start your server, or access a live branch
2. Open the Emails page
3. Click on a G Suite account
4. Click the Add new mailboxes option
5. Add one or several mailboxes to your shopping cart
6. Assert that the checkout looks like the screenshot above
7. Repeat steps #2–#6 with Google Workspace and Titan
8. Navigate to the Purchases page
9. Click on a G Suite subscription
10. Click the Renew now button
11. Assert that the checkout looks like the screenshot above
12. Repeat steps #8–#11 with Google Workspace and Titan
13. Navigate to the Domain Search page
14. Select a domain, then add either Google Workspace or Titan
15. Assert that the checkout looks like the screenshot above