Group window relayout requests

Various places in sysui might call into
NotificationShadeWindowController. Some of these calls can lead to
relayoutWindow(), which is quite expensive.

We should group these calls, and execute them in batch.

Test: manual
Test: perfetto trace
Test: atest NotificationPanelViewControllerTest
Test: atest NotificationShadeWindowControllerImplTest
Fixes: 190382751
Bug: 210432290
Change-Id: Ib08f7ba66048eb023ee2d5e9c09461381c390f0d