feat: add support for multiple roles during user creation (#7381)

#### What type of PR is this?

/kind feature
/area ui
/milestone 2.20.x

#### What this PR does / why we need it:

Add support for multiple roles during user creation

#### Which issue(s) this PR fixes:

Fixes #7325 

#### Does this PR introduce a user-facing change?

```release-note
新建用户时支持设置多个角色
```

ui/console-src/modules/system/users/components/UserCreationModal.vue

@@ -31,7 +31,6 @@ const formState = ref<CreateUserRequest>({
   password: "",
   roles: [],
 });
-const selectedRole = ref("");
 const isSubmitting = ref(false);
 
 onMounted(() => {
@@ -42,10 +41,6 @@ const handleCreateUser = async () => {
   try {
     isSubmitting.value = true;
 
-    if (selectedRole.value) {
-      formState.value.roles = [selectedRole.value];
-    }
-
     await consoleApiClient.user.createUser({
       createUserRequest: formState.value,
     });
@@ -122,10 +117,12 @@ const handleCreateUser = async () => {
           matches: $t('core.formkit.validation.password'),
         }"
       ></FormKit>
+      <!-- @vue-ignore -->
       <FormKit
-        v-model="selectedRole"
+        v-model="formState.roles"
         :label="$t('core.user.grant_permission_modal.fields.role.label')"
         type="roleSelect"
+        multiple
         validation="required"
       ></FormKit>
       <FormKit