Change log level of duplicate event reference id check.

Author: ejsmith

src/Exceptionless.Core/Plugins/EventProcessor/Default/05_CheckForDuplicateReferenceIdPlugin.cs

@@ -25,7 +25,7 @@ public override async Task EventProcessingAsync(EventContext context) {
                 return;
             }
 
-            _logger.LogWarning("Discarding event due to duplicate reference id: {ReferenceId}", context.Event.ReferenceId);
+            _logger.LogInformation("Discarding event due to duplicate reference id: {ReferenceId}", context.Event.ReferenceId);
             context.IsCancelled = true;
         }