Clean all missing scripts in Unity Gameobject, attached this script into the root of the gameobject. right click and call "RemoveMissingScript"

gistfile1.txt

    [ExecuteInEditMode]
    public class YourComponent : MonoBehaviour
    {
        [ContextMenu("remove missing script")]
        public void RemoveMissingScript()
        {
            var transforms = GetComponentsInChildren<Transform>(true);
            foreach (var childTransform in transforms)
            {
                var components = childTransform.GetComponents<Component>();
                var hasMissingScript = false;
                for (int i = 0; i < components.Length; i++)
                {
                    if (components[i] == null)
                    {
                        hasMissingScript = true;
                        break;
                    }
                }

                if (hasMissingScript)
                {
                    GameObjectUtility.RemoveMonoBehavioursWithMissingScript(childTransform.gameObject);
                }
            }
        }
  }