ISTWCMS-7252: Using permission for accessing custom form users page

uw_custom_forms.permissions.yml

+access uw custom forms user settings:
+  title: 'Access UW custom forms user settings'
+  description: 'Access the list of users per uw custom forms.'

uw_custom_forms.routing.yml

@@ -11,7 +11,7 @@ admission_requirements_form.users:
     _form: '\Drupal\uw_custom_forms\Form\AdmissionRequirementsFormUsers'
     _title: 'Admission requirements user settings'
   requirements:
-    _custom_access: '\Drupal\uw_custom_forms\Form\AdmissionRequirementsFormUsers::access'
+    _permission: 'access uw custom forms user settings'
 admission_requirements_form.settings:
   path: '/admin/config/admission-requirements-form/settings'
   defaults: