Improve multi-channel playback compatibility in WASAPI exclusive mode

[kashiken]

This PR improves playback compatibility for multi-channel audio devices in WASAPI exclusive mode.

Purpose of Change

In the current code, dwChannelMask in the WaveFormatExtensible constructor is set by simply shifting and OR-ing bits based on the number of channels.
However, actual multi-channel audio devices return values that differ from this, because Windows expects the standard speaker placements defined in ksmedia.h and devices follow that specification.

Changes

• Add an optional channelMask argument to the WaveFormatExtensible constructor.
  • If channelMask is not zero, dwChannelMask will be set to channelMask.
  • Otherwise, dwChannelMask is set as before.
• Extend GetFallbackFormat() to try additional channel masks as well as sampling rates, channel counts, and bit depths.
  • The candidates are taken from ksmedia.h in the Windows Driver Kit 10.0.19041.0.
  • The related documentation can be found here: https://learn.microsoft.com/en-us/windows-hardware/drivers/ddi/ksmedia/ns-ksmedia-waveformatextensible

Tests

Tested with a 4-channel USB audio device (channel mask 0x33 = KSAUDIO_SPEAKER_QUAD).
It cannot play back in WASAPI exclusive mode with the current code, but playback works after this change.