fix no sound issue in monochannel case

pyannote_viewer/frontend/Index.svelte

@@ -106,7 +106,6 @@
 		minPxPerSec: 20,
 		mediaControls: waveform_options.show_controls,
 		sampleRate: waveform_options.sample_rate || 44100,
-		splitChannels: true,
 	};
 
 

pyannote_viewer/frontend/player/AudioPlayer.svelte

@@ -58,6 +58,7 @@
 		waveform = WaveSurfer.create({
 			container: container,
 			media: audio,
+			splitChannels: value.multichannel,
 			...waveform_settings
 		});
 	};
@@ -81,6 +82,10 @@
 		splitter = audioContext.createChannelSplitter(numChannels);
 		mediaNode.connect(splitter);
 
+		if(!value.multichannel){
+			splitter.connect(audioContext.destination, 0);
+		}
+
 		// add diarization annotation on each source:
 		if(!wsRegion){
 			wsRegion = waveform.registerPlugin(RegionsPlugin.create())