Fix ClassCastException in QuickstepModelDelegate

- Added a casting check as an immediate fix to b/173838775
- Added logging to help debug the corrupt state where an item of type other than FolderInfo is used as an other item's container.
- Added LoaderMemoryLogger for adding large logs that are only conditionally printed.

Bug: 173838775
Test: manually checked logs
Change-Id: I9491cb421b9fb807d5fb110b04ad069481de768f