SystemUI: various qs tile detail improvements

- Handle top padding inside QSDragPanel, so the detail clipping animation
doesn't get cut off by the top padding.

- Increase bottom padding of the QSContainer to give some more
breathing room for the circle page indicator.

- Disable pager overscrolling

- Add dual tile carrot indicators to cast, dnd, and mobile data tiles

Change-Id: I81f56760140a2d7dd31e25b23f477eb1be0af305
Signed-off-by: Roman Birg <roman@cyngn.com>