Update BT audio policy configuration

Fix LE audio ports specificiation in
bluetooth_audio_policy_configuration.xml.
Add a note that BLE_HEADSET/SPEAKER devices are not valid
in audio HALs prior to V7.

Updated the V7 version of the BT configuration
to match the pre-V7 version.

Test: hardware/interfaces/audio/7.0/config/update_audio_policy_config.sh \
      device/google/bonito/audio_policy_configuration_a2dp_offload_disabled.xml \
      6.0
Change-Id: I1d526e7b19a77f2d923e330cd4226f11b449af2f