Add system properties to config headsetclient behaviors

add headset_client_initial_audio_route_allowed and
set headset_client_initial_audio_route_allowed to false for testing.

Bug: 264710028
Test: make a phone call with local build
(cherry picked from https://android-review.googlesource.com/q/commit:0a62f138e6f8e897d90e15733a3acc40682ad498)
Merged-In: Ie7179cbe3d3cb157bf1456b3db13a4f9acdf8e63
Change-Id: Ie7179cbe3d3cb157bf1456b3db13a4f9acdf8e63
Bug: 263323082