fix: world cardinal dev not exit on compilation error (#63)

Closes: WORLD-1079

## Overview

Fix `world cardinal dev` is not exited when there is a compilation error, user don't need to send sigint/sigterm to exit the process.

## Brief Changelog

- add step to send signterm when `cmd.Exec` process is done / exited
- skip killing the `cmd.Exec` if process is already exited.

## Testing and Verifying

Manually tested by running `world cardinal dev`

cmd/world/cardinal/dev.go

@@ -136,6 +136,17 @@ var devCmd = &cobra.Command{
 			return err
 		}
 
+		// Start a goroutine to check cmd is stopped
+		go func() {
+			err := execCmd.Wait()
+			if err != nil {
+				logger.Error(eris.Wrap(err, "Cardinal process stopped"))
+			}
+
+			// if process exited, send signal to StopChan
+			signalCh <- syscall.SIGTERM
+		}()
+
 		// Start a goroutine to listen for signals
 		go func() {
 			<-signalCh
@@ -255,6 +266,10 @@ func stopCardinal(cmd *exec.Cmd, watch bool) error {
 		return nil
 	}
 
+	if cmd.ProcessState == nil || cmd.ProcessState.Exited() {
+		return nil
+	}
+
 	// stop the cardinal process
 	if runtime.GOOS == "windows" {
 		err := cmd.Process.Kill()

cmd/world/root/root_test.go

@@ -214,7 +214,7 @@ func TestDev(t *testing.T) {
 	assert.NilError(t, err)
 
 	// Start cardinal dev
-	rootCmd.SetArgs([]string{"cardinal", "dev", "--watch"})
+	rootCmd.SetArgs([]string{"cardinal", "dev"})
 	go func() {
 		err := rootCmd.Execute()
 		assert.NilError(t, err)
@@ -238,7 +238,7 @@ func TestDev(t *testing.T) {
 	assert.Assert(t, isGameLoopRunning)
 
 	// Shutdown the program
-	close(cardinal.StopChan)
+	cardinal.StopChan <- struct{}{}
 
 	// Check cardinal health (expected error), trying for 10 times
 	count := 0