Fix RuntimeException in Special:Newitem with SpamBlacklist

All of the tests seem to miss this again as it only
appears when using the SpamBlackList hook!

This change reverts the change of behaviour introduced
by change Iacd00a3aa3d48b54f8e

Previous to the above change wbEntityId was '' if
there was no entity ID!
Previously we used getFormattedIdForEntity in EntityView
which still returns this '' when there is no entityid!

Bug: 62965
Change-Id: I5779ffc845de9c85418ae760ced03d43543f41c6
Merge "Fix RuntimeException in Special:Newitem with SpamBlacklist"