[chore][receiver/datadog] Fix data race detected in tests (#34834)

**Description:** <Describe what has changed.>
Fixes #34823

**Link to tracking Issue:** <Issue number if applicable>

**Testing:** <Describe what testing was performed and which tests were
added.>

**Documentation:** <Describe the documentation added.>

receiver/datadogreceiver/receiver_test.go

@@ -115,9 +115,6 @@ func TestDatadogServer(t *testing.T) {
 }
 
 func TestDatadogInfoEndpoint(t *testing.T) {
-	cfg := createDefaultConfig().(*Config)
-	cfg.Endpoint = "localhost:0" // Using a randomly assigned address
-
 	for _, tc := range []struct {
 		name            string
 		tracesConsumer  consumer.Traces
@@ -214,6 +211,9 @@ func TestDatadogInfoEndpoint(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
+			cfg := createDefaultConfig().(*Config)
+			cfg.Endpoint = "localhost:0" // Using a randomly assigned address
+
 			dd, err := newDataDogReceiver(
 				cfg,
 				receivertest.NewNopSettings(),