Cleanup wlinfo_oncreate flag.

The flag wlinfo_oncreate (com.android.window.flags) is eligible for
cleanup. Remove the flag and its references from the codebase.

Bug: 337820752
Bug: 423986902
Flag: EXEMPT cleanup
Test: atest FrameworksCoreDeviceStateManagerTests:DeviceStateManagerGlobalTest
Test: atest FrameworksServicesTests:DeviceStateManagerServiceTest
Change-Id: Ib8b725f1f942007ff9d10f7197649aab1eec3106