Send sysui state for all display when launcher connects

Previosuly we were just sending the SysUI State for the default display. Now we're sending it for all displays (only if the flag is on).

I regret having to make "notifySysUiStateFlagsForAllDisplays" public, but it seems there is no resonable way to trigger onServiceConnected from tests.

+ renamed the SysUIState to "DefaultSysUIState", and getting it from the PerDisplayRepository (but it's exactly the same instance while the flag is off.

+ Make FakeDisplayRepository have the default display at first.

Bug: 362719719
Bug: 398011576
Test: LauncherProxyServiceTest
Flag: com.android.systemui.shade_window_goes_around
Change-Id: I2717ad32077412a88e5d0a45e4f206725a217c95