Don't include user's email address in analytics data

[barbaranelson]

UI analytics data should not include personally identifiable information (such as the user's email address).

[jzahnd]

@jzahnd will follow up with data team to see if we have any dependencies on the user email address before moving forward.

[drdelambre]

we're using it in tools to segment internal users from external users. we will have to fill that information gap with something