Media streaming audio format default Pcm24kMono changed to null. (Azure#43796)

* Media streaming audio format default Pcm24kMono changed to null.

* removing the live test

* removing unused import

---------

Co-authored-by: Vinothini Dharmaraj <[email protected]>

Author: v-pivamshi

sdk/communication/azure-communication-callautomation/src/main/java/com/azure/communication/callautomation/CallAutomationAsyncClient.java

@@ -34,7 +34,6 @@
 import com.azure.communication.callautomation.implementation.models.TranscriptionTransportTypeInternal;
 import com.azure.communication.callautomation.models.AnswerCallOptions;
 import com.azure.communication.callautomation.models.AnswerCallResult;
-import com.azure.communication.callautomation.models.AudioFormat;
 import com.azure.communication.callautomation.models.CallInvite;
 import com.azure.communication.callautomation.models.CallLocator;
 import com.azure.communication.callautomation.models.CallLocatorKind;
@@ -325,9 +324,9 @@ private CreateCallRequestInternal getCreateCallRequestInternal(CreateGroupCallOp
                 MediaStreamingTransportTypeInternal.fromString(mediaStreamingOptions.getTransportType().toString()))
             .setStartMediaStreaming(mediaStreamingOptions.isStartMediaStreamingEnabled())
             .setEnableBidirectional(mediaStreamingOptions.isEnableBidirectional())
-            .setAudioFormat(mediaStreamingOptions.getAudioFormat() != null
-                ? AudioFormatInternal.fromString(mediaStreamingOptions.getAudioFormat().toString())
-                : AudioFormatInternal.fromString(AudioFormat.PCM_24K_MONO.toString()));
+            .setAudioFormat(AudioFormatInternal.fromString(mediaStreamingOptions.getAudioFormat() != null
+                ? mediaStreamingOptions.getAudioFormat().toString()
+                : null));
     }
 
     private TranscriptionOptionsInternal getTranscriptionOptionsInternal(TranscriptionOptions transcriptionOptions) {