feat(email): Add second warning delete account notice

[vbudhram]

Because

• We want to send a 2nd notice that Mozilla account will be delete because of inactivity

This pull request

• Adds the email template

Issue that this pull request solves

Closes: https://mozilla-hub.atlassian.net/browse/FXA-10637

Checklist

• My commit is GPG signed.
• If applicable, I have modified or added tests which pass locally.
• I have added necessary documentation (if appropriate).
• I have verified that my changes render correctly in RTL (if appropriate).

Screenshots (Optional)

[vpomerleau]

Found some small nits and content that was updated in Figma during initial email review

[vpomerleau]

Thanks for the updates! As we talked about on Slack, we'll need to add l10n for the previews and update one of the strings that was changed on Figma since I worked on the first email. Could be done here or in a quick follow-up.