OEL-1147: Add neutral variant in component library settings.

oe_whitelabel.theme

@@ -111,7 +111,7 @@ function oe_whitelabel_form_system_theme_settings_alter(&$form, FormStateInterfa
       'ec' => t('European Commission'),
       'eu' => t('European Union'),
     ],
-    '#default_value' => theme_get_setting('component_library'),
+    '#default_value' => theme_get_setting('component_library') ?? 'eu',
     '#description' => t('Choose "European Commission" for websites hosted under the ec.europa.eu domain and "European Union" for websites hosted under the europa.eu domain.'),
   ];
   $form['header_style'] = [