#5441551 Use “Email” instead of “Titan Mail”

Changes proposed in this Pull Request

• This PR replaces uses of “Titan Mail” and “Titan” with “Email”
• I also added the correct logo and colour for the Email icon on the email comparison page

This PR does not include a “Powered by Titan” logo/sticker for the email comparison page, which was something we should probably add.

Screenshots

Testing instructions

Check all the things… 😉

More seriously, check that when the titan/phase-2 feature flag is enabled (which it should be in wpcalypso and calypso.live), the following places in the UI reference “Email” and not “Titan”:

• The email comparison page for a domain that doesn’t have email configured yet
• The error message/warning when trying to cancel a domain that has Titan mail configured
• The domain listing page should use “Email” in the Email column for domains that have Titan email, and the popover for the Email column should use “Email” (I also tweaked the language here slightly)
• The domain management page should use “Email” if the domain has Titan email configured
• The new navigation menu should use a title of “Email”
• The mailbox quantity selection page should use “Email”
• The card for showing the embedded control panel (which can be enabled via the titan/iframe-control-panel flag) should use Email
• The card for showing a link to the Titan control panel (outside of the nav) should use “Email”. (This will likely need the titan/phase-2 feature flag to be disabled.)