[Chipbar] Enable chipbar to handle chipbars with different priorities.

This CL re-writes almost everything about how chipbar works,
unfortunately. I realized there were some bugs in the implementation of
handling multiple chipbars at once, and with the addition of priorities
it made it easier to just start from scratch.

Fixes: 261895766
Fixes: 258019006

Test: ttt chipbar then active unlock chipbar -> active unlock chipbar
shown, ttt chipbar re-shows after the active unlock chipbar disappears
Test: active unlock chipbar then ttt chipbar -> active unlock chipbar
still displayed, ttt chipbar shows up after active unlock disappears
Test: ttt flow from started -> triggered -> succeeded
Test: ttt flow works for multiple IDs
Test: ttt chipbar, then active unlock chipbar, then ttt chipbar with
updated info -> when active unlock chipbar disappears, ttt chipbar with
updated info *and updated timeout* is displayed
Test: atest TemporaryViewDisplayControllerTest

Change-Id: I7f077f7e05834c34cfd05ab72e307d2798a18ddf