Show intro and footer string according to the device's supported status

Bug: 390078046
Bug: 386121967
Test: atest HearingAidHelperTest HearingDeviceFooterPreferenceControllerTest HearingDeviceIntroPreferenceControllerTest BluetoothDetailsHearingDeviceSettingsControllerTest
Flag: EXEMPT bugfix
Change-Id: I564cdb80cd14f4d2d8e882b64db939449c6936b7
Signed-off-by: Jie Wang <jie.x.wang@sony.com>
Signed-off-by: Jason Hsu <jasonwshsu@google.com>