Filter out users not on the LocalSite when sending e-mails.
Users who were previously listed as a reviewer on a review request

belonging to a LocalSite, or participated in the discussion, would

continue to receive e-mails related to the review request after removed

from the LocalSite. This isn't ideal, as they shouldn't have had any

access once removed.
We now filter out these users when sending an e-mail. Both the

target_people list and the review participants are considered when

filtering.

Unit tests pass. Prior to this, the new unit test would fail, including

the users not part of the LocalSite.