Fix password_policy fallback handling

The defined fallback is only affecting when no core=>capabilities is there.
But that is pretty unlikely while the password_policy entry can be missing often

Signed-off-by: Joas Schilling <coding@schilljs.com>

src/components/NcPasswordField/NcPasswordField.vue

@@ -127,7 +127,7 @@ import { generateOcsUrl } from '@nextcloud/router'
 import { t } from '../../l10n.js'
 import logger from '../../utils/logger.js'
 
-const defaultPasswordPolicy = loadState('core', 'capabilities', { passwordPolicy: null }).password_policy
+const defaultPasswordPolicy = loadState('core', 'capabilities', { password_policy: null })?.password_policy || null
 
 export default {
 	name: 'NcPasswordField',