Dismiss Ongoing Notifications

Allow to individually dismissing Ongoing Notifications while the device
is unlocked. Notifications marked with FLAG_NO_DISMISS are exempted from
this feature.

This is behind the flag: SystemUiSystemPropertiesFlags.NotificationFlags.ALLOW_DISMISS_ONGOING

Bug: 240553971
Test: enable the flag, post some ongoing notifications, try to dismiss them from the locked and unlocked state
Test: atest BubblesTest DismissibilityCoordinatorTest ExpandableNotificationRowTest

Change-Id: I41e312421a88b6d867df61c279166b7181dd614e