Fixed pitch being doubled sometimes for mono sounds.

This is a more reliable fix than https://github.com/mono/MonoGame/pull/1940.
`AudioFileStream.StreamBasicDescription` (aka `DataFormat`) sometimes returns invalid properties `BytesPerPacket`, `BytesPerFrame`, `ChannelsPerFrame`. They are negative or zero. Mono sound is treated as stereo and its pitch becomes doubled.

Related bug: [Failed to get buffer attributes error when playing sounds](https://bugzilla.xamarin.com/show_bug.cgi?id=11074)
Related issue: https://github.com/mono/MonoGame/issues/1123

`AVAudioPlayer` can be used to get these properties reliably except `AudioFileStream.DataByteCount`.