[chore] Fix datadog receiver flakey test. (open-telemetry#23336)

* Use random address

* Bind to localhost interface

cmd/otelcontribcol/receivers_test.go

@@ -29,6 +29,7 @@ import (
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/azuremonitorreceiver"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/carbonreceiver"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/chronyreceiver"
+ "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/filelogreceiver"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/jmxreceiver"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/mongodbatlasreceiver"
@@ -157,6 +158,11 @@ func TestDefaultReceivers(t *testing.T) {
  },
  {
  receiver: "datadog",
+ getConfigFn: func() component.Config {
+ cfg := rcvrFactories["datadog"].CreateDefaultConfig().(*datadogreceiver.Config)
+ cfg.Endpoint = "localhost:0" // Using a randomly assigned address
+ return cfg
+ },
  },
  {
  receiver: "docker_stats",