Updated tests, only set baggage if it's in use

Author: mhelleborg

src/Proto.OpenTelemetry/OpenTelemetryDecorators.cs

@@ -313,7 +313,8 @@ internal static async Task Receive(string source, MessageEnvelope envelope, Acti
 
         var propagationContext = envelope.Header.ExtractPropagationContext();
 
-        if (propagationContext.Baggage.Count > 0)
+        bool hasBaggage = propagationContext.Baggage.Count > 0 || Baggage.Current.Count > 0;
+        if (hasBaggage)
         {
             Baggage.Current = propagationContext.Baggage;
         }

tests/Proto.OpenTelemetry.Tests/OpenTelemetryTracingTests.cs

@@ -188,9 +188,10 @@ await VerifyTrace(async (tracedRoot, target) =>
                     await next(context, target, updatedEnvelope);
                 });
                 var future = new FutureProcess(middleContext.System);
+                Baggage.Current = TestBaggage;
                 middleContext.Request(target, new TraceMe(SendAs.Request), future.Pid);
                 var response = (MessageEnvelope)await future.Task;
-                response.Message.Should().Be(new TraceResponse());
+                response.Message.Should().Be(new TraceResponse(TestBaggage));
             }
         );