feat(conference): Add stop/start transcriber methods

JitsiConference.js

@@ -1741,6 +1741,19 @@ JitsiConference.prototype.hangup = function() {
     });
 };
 
+/**
+ * Starts the transcription service.
+ */
+JitsiConference.prototype.startTranscriber = function() {
+    return this.dial('jitsi_meet_transcribe');
+};
+
+
+/**
+ * Stops the transcription service.
+ */
+JitsiConference.prototype.stopTranscriber = JitsiConference.prototype.hangup;
+
 /**
  * Returns the phone number for joining the conference.
  */