Fix audio upload when no audio in input dir (#3891)

web/extensions/core/uploadAudio.js

@@ -145,7 +145,9 @@ app.registerExtension({
           )
         }
         // Initially load default audio file to audioUIWidget.
-        onAudioWidgetUpdate()
+        if (audioWidget.value) {
+          onAudioWidgetUpdate()
+        }
         audioWidget.callback = onAudioWidgetUpdate
 
         const fileInput = document.createElement("input")