Maximize USB audio volume when connecting.

Some of the USB audio devices have low hardware volume by default. If
the audio system doesn't set the hardware volume, the user will not be
able to get the full range of volume that is supported by the device.

Bug: 245041322
Test: connect USB device with default low hw volume
Flag: com.android.server.usb.flags.maximize_usb_audio_volume_when_connecting
Change-Id: I86874254c31bfb009ad7c36add11f8ab6496fe96