Add hfp sysprop for hf_client_features

The `define` cannot be override on runtime and some target need to
configure the features (Eg: Wear OS)

Test: atest net_test_bta net_test_btif_hf_client_service
Test: manual | set the property and check new behavior
Bug: 263323082
Change-Id: Ic241364ceed263138797e3c3ad0f139da67e689a