We already know which list widget a `<th>`
tag is associated with when we set up the
event handler, so it's silly to read data
from the DOM to find that widget again
when the handler runs.
This commit eliminates a whole class of possible
errors and busy work.
In the emails-hidden case, for non-admins, we should remove the email
field from "Users" list in the organization settings page.
Tweaked by tabbott to correctly handle the bots and deactivated users pages.
Steve Howell
Thomas Ip
Pragati Agrawal
Anders Kaseorg