Slide in first page preview items in FolderIcon after Folder closes.

If the Folder is not closed on on the first page, we animate the
current page items as if they are in the preview.

When the Folder finishes closing, the first page preview items
slide in as the current page preview items slide out.

Bug: 36022592
Bug: 35064148
Change-Id: I7ede7ed9e091e2a0c3cbe11731744bfe9ce36595