[sdk-debug] Add EventWrittenEventArgs.Level to the EventListener debu…

…g output (#4617)

src/OpenTelemetry/Internal/OpenTelemetrySdkEventSource.cs

@@ -358,7 +358,7 @@ protected override void OnEventWritten(EventWrittenEventArgs e)
                     message = e.Message;
                 }
 
-                Debug.WriteLine($"{e.EventSource.Name} - EventId: [{e.EventId}], EventName: [{e.EventName}], Message: [{message}]");
+                Debug.WriteLine($"{e.EventSource.Name} - Level: [{e.Level}], EventId: [{e.EventId}], EventName: [{e.EventName}], Message: [{message}]");
             }
         }
 #endif