Avoid PHP notices about unset indexes in ApiPageTriageList
Avoid PHP notices about unset indexes in ApiPageTriageList

This fixes problems introduced in Icfd6aea.

Also fix bug when a count is requested for neither reviewed nor
unreviewed files.

Also improve comments about excluding redirects and deleted pages
so it is less confusing.

Change-Id: I40772e546c637f6855bfe53933c16811cff8ad85

wikimedia/mediawiki-extensions-PageTriage,wikimedia/mediawiki-extensions-PageTriage,wikimedia/mediawiki-extensions-PageTriage