### Godot version

4.2.dev2

### System information

Godot v4.2.dev2 - Windows 10.0.19044 - GLES3 (Compatibility) - AMD Radeon(TM) Vega 8 Graphics (Advanced Micro Devices, Inc.; 31.0.14051.5006) - AMD Ryzen 5 2500U with Radeon Vega Mobile Gfx (8 Threads)

### Issue description

4.2.dev1 will not crash.
When running the following code, because `FileAccess.open`cannot create a folder, it will return a null, and the debugger will trigger a breakpoint, causing the editor to crash.
```gdscript
extends Node

func _ready() -> void:
	var f := FileAccess.open("user://log/log.gd",FileAccess.READ_WRITE)
	print(f.get_open_error())

	#var fok:FileAccess = null # This is ok.
	#print(fok.get_open_error())
```
backtrace
```
godot_windows_editor_x86_64!EncodedObjectAsID::get_object_id
godot_windows_editor_x86_64!EditorDebuggerInspector::add_stack_variable
godot_windows_editor_x86_64!ScriptEditorDebugger::_parse_message
godot_windows_editor_x86_64!ScriptEditorDebugger::_notification
godot_windows_editor_x86_64!ScriptEditorDebugger::_notificationv
godot_windows_editor_x86_64!Object::notification
godot_windows_editor_x86_64!SceneTree::_process_group
godot_windows_editor_x86_64!SceneTree::_process
godot_windows_editor_x86_64!SceneTree::process
godot_windows_editor_x86_64!Main::iteration
godot_windows_editor_x86_64!OS_Windows::run
godot_windows_editor_x86_64!widechar_main
godot_windows_editor_x86_64!_main
godot_windows_editor_x86_64!main
godot_windows_editor_x86_64!invoke_main
godot_windows_editor_x86_64!__scrt_common_main_seh
KERNEL32!BaseThreadInitThunk
ntdll!RtlUserThreadStart
```

### Steps to reproduce

1. Add the above code to the project and run it. The debugger will encounter an error and crash. 
2. Test the commented code, but the editor will not crash.

### Minimal reproduction project

N/A
#include "editor_debugger_inspector.h"
#include "core/debugger/debugger_marshalls.h"
#include "core/io/marshalls.h"
#include "editor/editor_node.h"
#include "scene/debugger/scene_debugger.h"
bool EditorDebuggerRemoteObject::_set(const StringName &p_name, const Variant &p_value) {
	if (!prop_values.has(p_name) || String(p_name).begins_with("Constants/")) {
		return false;
	}
	prop_values[p_name] = p_value;
	emit_signal(SNAME("value_edited"), remote_object_id, p_name, p_value);
	return true;
}
bool EditorDebuggerRemoteObject::_get(const StringName &p_name, Variant &r_ret) const {
	if (!prop_values.has(p_name)) {
		return false;
	}
	r_ret = prop_values[p_name];
	return true;
}
void EditorDebuggerRemoteObject::_get_property_list(List<PropertyInfo> *p_list) const {