### Godot version

3.5.1mono

### System information

windows10

### Issue description

Error message
 scene/main/node.cpp:1362 - Index p_index = 0 is out of bounds (data.children.size() = 0).
 scene/main/node.cpp:397 - Parameter "p_child" is null.
 scene/gui/tab_container.cpp:593 - Index p_current = 0 is out of bounds (get_tab_count() = 0).
See "Steps to reproduce for details"

### Steps to reproduce

Set an external text editor
Create a script
Drop the script to the built-in text editor like this image:
![image](https://user-images.githubusercontent.com/119792950/209504041-039f2620-5e42-4c0f-8c41-cd24486fb3d2.png)
And got error message:
 scene/main/node.cpp:1362 - Index p_index = 0 is out of bounds (data.children.size() = 0).
 scene/main/node.cpp:397 - Parameter "p_child" is null.
 scene/gui/tab_container.cpp:593 - Index p_current = 0 is out of bounds (get_tab_count() = 0).

### Minimal reproduction project

An empty project
for (int i = 0; i < tab_container->get_tab_count(); i++) {
		EditorHelp *eh = Object::cast_to<EditorHelp>(tab_container->get_tab_control(i));
		if (eh && eh->get_class() == p_name) {
			_go_to_tab(i);
			eh->go_to_help(p_desc);
			_update_script_names();
			return true;
		}
	}
	return false;
}
void ScriptEditor::update_doc(const String &p_name) {
	ERR_FAIL_COND(!EditorHelp::get_doc_data()->has_doc(p_name));
	for (int i = 0; i < tab_container->get_tab_count(); i++) {
		EditorHelp *eh = Object::cast_to<EditorHelp>(tab_container->get_tab_control(i));
		if (eh && eh->get_class() == p_name) {
			eh->update_doc();
			return;
		}
	}
}
void ScriptEditor::clear_docs_from_script(const Ref<Script> &p_script) {