Remove PubSub MQTT startup repeat (#1547)

This can cause considerable slowdown when connecting to multiple MQTT
destinations or when waiting for pubsub application to start, and is
unecessary.

Instead, the DisconnectHandler fires on connect fail as well, so this
implementation works.

Libraries/Opc.Ua.PubSub/Transport/MqttClientCreator.cs

@@ -99,12 +99,6 @@ internal class MqttClientCreator
                 }
             }
 
-            while (mqttClient.IsConnected == false)
-            {
-                await Connect(reconnectInterval, mqttClientOptions, mqttClient);
-                await Task.Delay(TimeSpan.FromSeconds(reconnectInterval)).ConfigureAwait(false);
-            }
-
             // Setup reconnect handler
             mqttClient.UseDisconnectedHandler(async e => {
                 await Task.Delay(TimeSpan.FromSeconds(reconnectInterval)).ConfigureAwait(false);
@@ -122,6 +116,8 @@ internal class MqttClientCreator
                 }
             });
 
+            await Connect(reconnectInterval, mqttClientOptions, mqttClient);
+
             return mqttClient;
         }