Floss: Fix headset that requires +CIEV command to work and cannot provide...

Floss: Fix headset that requires +CIEV command to work and cannot provide sound when Bluetooth Telephony is enabled

Some Bluetooth headsets require placing an active call to trigger +CIEV
to enable sound through HFP. However, the +CIEV workaround conflicts
with the initial state needed for Bluetooth Telephony, which requires
no call.

Originally, we removed the +CIEV workaround when the Bluetooth Telephony
feature flag was enabled. However, this could potentially cause a
regression for headsets requiring the +CIEV command when launching the
feature.

To avoid breaking the original use case for users who don't need
telephony, we restrict the +CIEV workaround removal to only when a user
explicitly enables UHID, which means the user intents to use Bluetooth
Telephony.

Bug: 340375662
Test: Conduct the following manual tests
  - enable bluetooth telephony
  - pair Bluetooth Headset need +CIEV command to work(Parrot Zik 2.0)
  - playback with youtube and online voice recorder and make sure hfp
  audio work
  - enable uhid and observe the hfp audio will not work
Test: atest bluetooth_test_gd
Tag: #floss
Flag: EXEMPT, no behavior change on Android; Floss-only changes

Change-Id: I41ea0d3ae61ec928bb099c5b6053c65f473bb764