Add email exposed key handling

[gjcthinkst]

Proposed changes

Add email support for exposed API key alerts.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update

Checklist

• Lint and unit tests pass locally with my changes (if applicable)
• I have run pre-commit (pre-commit in the repo)
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Linked to the relevant github issue or github discussion

Further comments

I tested the changes to the email handling by creating a new AWS API key token, triggering it normally and manually creating an exposed key alert with CURL (with 25 Dec as the exposed time) and checked that the normal alert email and the exposed key alert email were both correct.