To add support for #400, we're using the macadmins/osquery-extension to gather Google Chrome profiles from hosts.
Under the hood, the extension looks and parses a json file in which Chrome stores a bunch of data. Given that emails are not required to create Chrome profiles, some of the profiles stored in this file and returned by the query we're using contain empty emails.
The idea after this change is to prevent empty emails from being ingested in the first place instead of filtering them after the fact. I have also included a migration to clean the rows with empty email columns.
Fixes#4780
