ensure right ordering when asserting mule remote test (#7790)

Author: amarziali

dd-java-agent/instrumentation/mule-4/src/test/groovy/mule4/MuleForkedTest.groovy

@@ -93,6 +93,7 @@ class MuleForkedTest extends WithHttpServer<MuleTestContainer> {
     response.body().string() == "Hello Client."
     assertTraces(1) {
       trace(2) {
+        sortSpansByStart()
         span(0) {
           operationName operation()
           resourceName "GET /client-request"