[Elastic Agent] Trust exchange endpoint must bind to 127.0.0.1 (#19861)…

… (#19863)

Change the address bind from 0.0.0.0 (all) to 127.0.0.1.

(cherry picked from commit 64bf7fc)

x-pack/elastic-agent/pkg/core/plugin/service/app.go

@@ -305,7 +305,7 @@ func (a *Application) cleanUp() {
 }
 
 func (a *Application) startCredsListener() error {
- lis, err := net.Listen("tcp", fmt.Sprintf(":%d", a.credsPort))
+ lis, err := net.Listen("tcp", fmt.Sprintf("127.0.0.1:%d", a.credsPort))
  if err != nil {
  return errors.New(err, "failed to start connection credentials listener")
  }