refactor(frontend): use useTemplateRef for DOM referencing

packages/frontend/src/components/MkAbuseReportWindow.vue

@@ -30,7 +30,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 </template>
 
 <script setup lang="ts">
-import { ref, shallowRef } from 'vue';
+import { ref, useTemplateRef } from 'vue';
 import * as Misskey from 'misskey-js';
 import MkWindow from '@/components/MkWindow.vue';
 import MkTextarea from '@/components/MkTextarea.vue';
@@ -47,7 +47,7 @@ const emit = defineEmits<{
 	(ev: 'closed'): void;
 }>();
 
-const uiWindow = shallowRef<InstanceType<typeof MkWindow>>();
+const uiWindow = useTemplateRef('uiWindow');
 const comment = ref(props.initialComment ?? '');
 
 function send() {