feat: Add support for Voxtral Realtime 4B #82

Job	Run time
tests (VAD, MLXAudioTests/MLXAudioVADTests)	12m 24s
tests (STT, MLXAudioTests/MLXAudioSTTTests)	11m 21s
tests (Codecs, MLXAudioTests/MLXAudioCodecsTests)	9m 38s
tests (TTS, MLXAudioTests/MLXAudioTTSTests)	6m 49s
	40m 12s

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