[3.x] Fix Open Editor Data/Settings Folder menu in self-contained mode

[timothyqiu]

3.x version of #110413

[bruvzg]

It's using EditorSettings to open folders, so should use it for this check as well.

case SETTINGS_EDITOR_DATA_FOLDER: {
	OS::get_singleton()->shell_open(String("file://") + EditorSettings::get_singleton()->get_data_dir());
} break;
case SETTINGS_EDITOR_CONFIG_FOLDER: {
	OS::get_singleton()->shell_open(String("file://") + EditorSettings::get_singleton()->get_settings_dir());
} break;

[lawnjelly]

Thanks!