Sending synthesized-audio notification for servedFromCache as false (#1320)

* Sending synthesized-audio notification for servedFromCache as well
https://github.com/jambonz/jambonz-feature-server/issues/1319

* Sending back the id that was set, to track the synthesized-audio
e.g if we send a say verb having 100, it's synthesized-audio event will return 100 in the data to correleate the say verb and synthesized-audio event

lib/tasks/tts-task.js

@@ -293,7 +293,18 @@ class TtsTask extends Task {
                 vendor,
                 language,
                 characters: text.length,
-                elapsedTime: rtt
+                elapsedTime: rtt,
+                servedFromCache,
+                'id': this.id
+              });
+            }
+            if (servedFromCache) {
+              this.notifyStatus({
+                event: 'synthesized-audio',
+                vendor,
+                language,
+                servedFromCache,
+                'id': this.id
               });
             }
           }