fix(auth): new device email not sent after verify success

[toufali]

Because

• the "new device" email is not sent after successful email confirmation

This pull request

• adds the functionality

Issue that this pull request solves

Closes: FXA-12802

Other information (Optional)

See the original comment from @vpomerleau, who discovered the issue. From that comment, steps to repro:

1. Set env vars:
   SERVICES_WITH_EMAIL_VERIFICATION=dcdb5ae7add825d2
   SIGNIN_CONFIRMATION_SKIP_FOR_NEW_ACCOUNTS=false
2. Create a new account
3. Open new profile with the dev launcher (yarn firefox)
4. Go to 123Done (localhost:8080)
5. Sign in with email
6. Enter password

[vbudhram]

@toufali This sends email 👍🏽, might be useful to update the corresponding test to assert mailer called in this state.

[toufali]

@toufali This sends email 👍🏽, might be useful to update the corresponding test to assert mailer called in this state.

Thanks @vbudhram, test updated 👍