Apply delivery group policies to CLOSE_SYSTEM_DIALOG broadcast.

- The "set-defer-until-active" policy is applied so that the
broadcast targeted to apps in the Cached state is deferred until
they come out of that state.
- The "deliver-most-recent" policy is applied so that if there are
already pending broadcasts waiting to be delivered when a new
broadcast is sent, the old ones are discarded.

Bug: 271950524
Test: TH
Change-Id: I2c75498e93b6a04ddc631348cfb1cb9a4daec1fd