Fix accessibility violation in user modal

Add missing 'label-for', prop to select dropdown to
fix form accessibility issue.

Signed-off-by: Yoshie Muranaka <yoshiemuranaka@gmail.com>
Change-Id: I89a530bf67165c4051c7b773917b4d60d0d17a6f
diff --git a/src/views/AccessControl/LocalUserManagement/ModalUser.vue b/src/views/AccessControl/LocalUserManagement/ModalUser.vue
index ef13761..aacda11 100644
--- a/src/views/AccessControl/LocalUserManagement/ModalUser.vue
+++ b/src/views/AccessControl/LocalUserManagement/ModalUser.vue
@@ -70,8 +70,10 @@
             </b-form-group>
             <b-form-group
               :label="$t('pageLocalUserManagement.modal.privilege')"
+              label-for="privilege"
             >
               <b-form-select
+                id="privilege"
                 v-model="form.privilege"
                 :options="privilegeTypes"
                 :state="getValidationState($v.form.privilege)"