Add a new isAshaHearingAidSupported method to Bluetooth Manager

As part of adding isHearingAidsProfileSupported method to
BluetoothAdapter, this new method is added to query the support state.

Test: Manual testing with configuration enabled and disabled.
Bug: 119617521
Change-Id: I97151443c6a5bd459a7c73c61f7fa7d5a386909a
(cherry picked from commit 7d51ff78280a9e03949ffed8f7f61d5226c3a27b)