HFP client status update

When call events happen request the updated status from the Audio
Gateway immediately rather than waiting until a preset timer has
expired.

Bug: 68884780
Test: runtest bluetooth; make and end phonecalls and verify that the
UI updates promptly.

Change-Id: I619fbc447d53fc87af55b2616f9258dde399b1e7
(cherry picked from commit 7e00a402b76c9167784fe90c6d24fc88c42f5c5b)