Dashboard - Add some logging surrounding sheriff assignment.
Dashboard - Add some logging surrounding sheriff assignment.

We're seeing alerts generated for TestMetadata entities that seemingly have no sheriff. Logs indicate they actually have a sheriff at the time of the alert creation, so trying to see how this might happen.

Bug: catapult:#3903
Change-Id: Ie5dfefdf67efa4a2aae05e4a928912a0cca74e92
Reviewed-on: https://chromium-review.googlesource.com/690702
Reviewed-by: Annie Sullivan <259f984aa3b2892f452a20facda15d22b94ee4f8@chromium.org>
Commit-Queue: Simon Hatch <490a224d89645d3fea983d7189ce51bde0a00c1d@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult