AAP-45937 Make settings not required because they are not (#15998)

* Make settings not required because they are not, or should not be

awx/conf/registry.py

@@ -38,6 +38,7 @@ class SettingsRegistry(object):
         if setting in self._registry:
             raise ImproperlyConfigured('Setting "{}" is already registered.'.format(setting))
         category = kwargs.setdefault('category', None)
+        kwargs.setdefault('required', False)  # No setting is ordinarily required
         category_slug = kwargs.setdefault('category_slug', slugify(category or '') or None)
         if category_slug in {'all', 'changed', 'user-defaults'}:
             raise ImproperlyConfigured('"{}" is a reserved category slug.'.format(category_slug))