MM-14827 don't kill STDOUT for the server process (#10828)

cmd/mattermost/commands/server.go

@@ -91,7 +91,7 @@ func runServer(configStore config.Store, disableConfigWatch bool, usedPlatform b
 
 	// wait for kill signal before attempting to gracefully shutdown
 	// the running service
-	signal.Notify(interruptChan, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
+	signal.Notify(interruptChan, os.Interrupt, syscall.SIGINT, syscall.SIGTERM, syscall.SIGPIPE)
 	<-interruptChan
 
 	return nil