System.Speech should work with OneCore voices

[rampaa]

System.Speech doesn't work with OneCore voices out of the box. While the result of new SpeechSynthesizer().GetInstalledVoices(CultureInfo.GetCultureInfo("ja-JP")); includes Microsoft Haruka Desktop, it doesn't include Microsoft Ayumi, Microsoft Sayaka, etc. Support for OneCore voices can be added somewhat trivially with reflection, but ideally, we shouldn't need to use reflection at all, and System.Speech should support OneCore voices out of the box.

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