feat: Add version switch settings file to plugin initialization

Author: imantsk

src/php/class-plugin.php

@@ -114,6 +114,7 @@ public function load_plugin() {
 		// Settings component.
 		require_once $includes_path . '/settings/settings-fields.php';
 		require_once $includes_path . '/settings/editor-preview.php';
+		require_once $includes_path . '/settings/version-switch.php';
 		require_once $includes_path . '/settings/settings.php';
 
 		// Cloud List Table shared functions.