Apply the most-recent delivery policy to allowlist changed broadcasts.

Applying the policy to ACTION_POWER_SAVE_TEMP_WHITELIST_CHANGED and
ACTION_POWER_SAVE_WHITELIST_CHANGED broadcasts so that when dispatching
these broadcasts, we can discard any older broadcasts waiting
to be delivered and deliver only the most recent to the receivers.

Bug: 263809961
Test: TH
Change-Id: Id5e424fe2993ae92e5b65457db3c7c7c5d62901c