### Godot version

Godot Engine v4.0.stable.official.92bee43ad

### System information

Windows 10

### Issue description

The documentation states that passing ```null``` into the image parameter of ```set_custom_mouse_cursor``` will change it back to the system cursor, however I find that it removes the cursor's image entirely, rather than setting it to the system's cursor.


### Steps to reproduce

```var isimage = false
var theimage = load("res://final.png")

func _on_my_button_pressed():
    if isimage == false:
        Input.set_custom_mouse_cursor(theimage, Input.CURSOR_ARROW, Vector2(16,16))
        isimage = true
        
    else:
        Input.set_custom_mouse_cursor(null)
        isimage = false```

When the button is pressed, the cursor is meant to change to the new cursor. When it has been pressed a second time, it changes back to the default cursor. However, upon pressing it a second time, it simply disappears. The cursor becomes visible again when the cursor exits and re-enters the window.

### Minimal reproduction project

[null mouse.zip](https://github.com/godotengine/godot/files/10901969/null.mouse.zip)

ClientToScreen(wd.hWnd, (POINT *)&r.right);
			wd.last_pos = Point2i(r.left, r.top) - _get_screens_origin();
			wd.width = r.right - r.left;
			wd.height = r.bottom - r.top;
		} else {
			wd.last_pos = p_rect.position;
			wd.width = p_rect.size.width;
			wd.height = p_rect.size.height;
		}
		window_id_counter++;
	}
	return id;
}
bool DisplayServerWindows::wintab_available = false;
WTOpenPtr DisplayServerWindows::wintab_WTOpen = nullptr;
WTClosePtr DisplayServerWindows::wintab_WTClose = nullptr;
WTInfoPtr DisplayServerWindows::wintab_WTInfo = nullptr;
WTPacketPtr DisplayServerWindows::wintab_WTPacket = nullptr;
WTEnablePtr DisplayServerWindows::wintab_WTEnable = nullptr;
bool DisplayServerWindows::dark_title_available = false;
bool DisplayServerWindows::ux_theme_available = false;
ShouldAppsUseDarkModePtr DisplayServerWindows::ShouldAppsUseDarkMode = nullptr;
GetImmersiveColorFromColorSetExPtr DisplayServerWindows::GetImmersiveColorFromColorSetEx = nullptr;
GetImmersiveColorTypeFromNamePtr DisplayServerWindows::GetImmersiveColorTypeFromName = nullptr;
GetImmersiveUserColorSetPreferencePtr DisplayServerWindows::GetImmersiveUserColorSetPreference = nullptr;
bool DisplayServerWindows::winink_available = false;
GetPointerTypePtr DisplayServerWindows::win8p_GetPointerType = nullptr;
GetPointerPenInfoPtr DisplayServerWindows::win8p_GetPointerPenInfo = nullptr;
LogicalToPhysicalPointForPerMonitorDPIPtr DisplayServerWindows::win81p_LogicalToPhysicalPointForPerMonitorDPI = nullptr;
typedef enum _SHC_PROCESS_DPI_AWARENESS {