Extract SysUi state management out of OverviewProxyService

Move all sysUi state flag handling into a
separate class.

fixes: 138601608
Test: atest SysUiStateFlagsContainerTest
Checked that callbacks were being sent in
OPS, EdgeHandler and in Launcher codebase via
debugger.

Change-Id: Ie8f7ef2e647db88d244af1062eb95dbb69a46919