[ECO-5458] Updated ChangeEmitter implementations to be type safe

Author: sacOO7

live-objects/src/main/kotlin/io/ably/lib/objects/type/livecounter/LiveCounterChangeCoordinator.kt

@@ -42,7 +42,8 @@ private class LiveCounterChangeEmitter : EventEmitter<LiveCounterUpdate, LiveCou
 
   override fun apply(listener: LiveCounterChange.Listener?, event: LiveCounterUpdate?, vararg args: Any?) {
     try {
-      listener?.onUpdated(event!!)
+      event?.let { listener?.onUpdated(it) }
+        ?: Log.w(tag, "Null event passed to listener callback")
     } catch (t: Throwable) {
       Log.e(tag, "Error occurred while executing listener callback for event: $event", t)
     }

live-objects/src/main/kotlin/io/ably/lib/objects/type/livemap/LiveMapChangeCoordinator.kt

@@ -42,7 +42,8 @@ private class LiveMapChangeEmitter : EventEmitter<LiveMapUpdate, LiveMapChange.L
 
   override fun apply(listener: LiveMapChange.Listener?, event: LiveMapUpdate?, vararg args: Any?) {
     try {
-      listener?.onUpdated(event!!)
+      event?.let { listener?.onUpdated(it) }
+        ?: Log.w(tag, "Null event passed to listener callback")
     } catch (t: Throwable) {
       Log.e(tag, "Error occurred while executing listener callback for event: $event", t)
     }