Fix Division by Zero Error in audioOffsetMs Calculation (#857)

* bug fix on potential division by zero

* Update ServiceRecognizerBase.ts

typo fixed from != to !==

src/common.speech/ServiceRecognizerBase.ts

@@ -666,7 +666,7 @@ export abstract class ServiceRecognizerBase implements IDisposable {
 
     private updateSpeakerDiarizationAudioOffset(): void {
         const bytesSent: number = this.privRequestSession.recognitionBytesSent;
-        const audioOffsetMs: number = bytesSent / this.privAverageBytesPerMs;
+        const audioOffsetMs: number = this.privAverageBytesPerMs !== 0 ? bytesSent / this.privAverageBytesPerMs : 0;
         this.privSpeechContext.setSpeakerDiarizationAudioOffsetMs(audioOffsetMs);
     }