Adds the email domain to Amplitude click events. For privacy reasons, if the user's email address is not from one of the 20 most popular email domains, the property will be set to "other".
{"op":"amplitudeEvent","time":1522334772118,"user_id":"b1470df8f2084a43a05d5d5dec651954","device_id":"fefc7d2f398d4e5db060b8bdb4b72a1b","event_type":"fxa_email - click","session_id":1522334738721,"event_properties":{"device_id":"fefc7d2f398d4e5db060b8bdb4b72a1b","email_type":"registration","email_domain":"gmail.com","service":"sync"},"user_properties":{"ua_browser":"Firefox","ua_version":"58.0","entrypoint":"menupanel","$append":{"experiments":["q3form_changes_email_first"]},"flow_id":"5d7cf91a38da66f47d3a6cca970f4250ac3158adcd0b178e072873dfc994bd83"},"app_version":"108","language":"en","os_name":"Mac OS X","os_version":"10.11"}
{"op":"amplitudeEvent","time":1522334706317,"user_id":"5e88cdb99b9043ef8270360de02bcad5","device_id":"9fe352240dc04c4cbc5a9f6637988941","event_type":"fxa_email - click","session_id":1522334666531,"event_properties":{"device_id":"9fe352240dc04c4cbc5a9f6637988941","email_type":"registration","email_domain":"other","service":"sync"},"user_properties":{"ua_browser":"Firefox","ua_version":"58.0","entrypoint":"menupanel","$append":{"experiments":["q3form_changes_email_first"]},"flow_id":"7074e012c0ff7503f5b1006772d636b713dee6093e5477745a6b9f142a97f27b"},"app_version":"108","language":"en","os_name":"Mac OS X","os_version":"10.11"}