Fix the user being asked 4 times for a password when adding a secondary email...

Fix the user being asked 4 times for a password when adding a secondary email to a primary account and verifying email ownership in a new browser.

* When "email_staged" is triggered, trigger it with the password.
* Rename helpers.addSecondaryEmailWithPassword to helpers.addSecondaryEmail
* Add unit tests for helpers.addSecondaryEmail
* Yak shave the unit tests to clean them up so that they are easier to follow.

issue #1555