### 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)

SHC_PROCESS_DPI_UNAWARE = 0,
	SHC_PROCESS_SYSTEM_DPI_AWARE = 1,
	SHC_PROCESS_PER_MONITOR_DPI_AWARE = 2
} SHC_PROCESS_DPI_AWARENESS;
bool DisplayServerWindows::is_dark_mode_supported() const {
	return ux_theme_available;
}
bool DisplayServerWindows::is_dark_mode() const {
	return ux_theme_available && ShouldAppsUseDarkMode();
}
Color DisplayServerWindows::get_accent_color() const {
	if (!ux_theme_available) {
		return Color(0, 0, 0, 0);
	}
	int argb = GetImmersiveColorFromColorSetEx((UINT)GetImmersiveUserColorSetPreference(false, false), GetImmersiveColorTypeFromName(L"ImmersiveSystemAccent"), false, 0);
	return Color((argb & 0xFF) / 255.f, ((argb & 0xFF00) >> 8) / 255.f, ((argb & 0xFF0000) >> 16) / 255.f, ((argb & 0xFF000000) >> 24) / 255.f);
}
int DisplayServerWindows::tablet_get_driver_count() const {