Reports: Fix logic for age histogram bucket creation
When the oldest open task is more recent than the
oldest bucket, a bogus bucket row was created at
the bottom.
Avoid by explicitly setting $max_age
to the
time difference since epoch.
Remove createdStart URL parameter from the query URL of the 'Older' bucket, as Phabricator Search will not accept week values > 52 (epoch was more than 52 weeks ago).
Bug: T336152