Show migrated items on the last page

If the hotseat migration is unable to find an existing page, it creates
a new page and move the items there. This is fixing an issue where items
migrated to a new page don't show up as we are using
mLauncher.bindAppsAdded instead of rebinding the workspace.

Bug: 142753423
Test: Manual
Change-Id: Ia812585f28b9b7e3e6cb4966770a1996eadd03a5