(bug 49164) Filters don't refresh feedback list any more

https://gerrit.wikimedia.org/r/#/c/63480/ introduced getTitleOrPageId. The API
now accepts both pageid & title. Parts of the code are still expecting
$params['pageid'] though.

As a result, instead of "null" (= central feedback page) as pageId, it was 0 in
ApiViewFeedbackArticleFeedbackv5.php, which in turn led to wrong data being
pulled from the cache (cache for pageId 0 is never purged, since it should be
null, so cache is never updated)

Bug: 49164
Change-Id: Id5b5a7f85b73ac27ad6cf4ab1b380802813b9683
Merge "(bug 49164) Filters don't refresh feedback list any more"