Fixed an issue where the panel height was wrong

Because we wouldn't get a layout call when collapsing
the shade when we had a bubble, the panel would keep
the existing content height, because we didn't notify
it of the change properly.

Fixes: 128156368
Test: atest SystemUITests
Change-Id: Ib529f22074fcdd3a2f879fe8e10b12bff2c7950d