refactor(frontend): use PageWithHeader instead of MkStickyContainer+MkPageHeader combination

packages/frontend/src/pages/flash/flash-edit.vue

@@ -4,8 +4,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 -->
 
 <template>
-<MkStickyContainer>
-	<template #header><MkPageHeader :actions="headerActions" :tabs="headerTabs"/></template>
+<PageWithHeader :actions="headerActions" :tabs="headerTabs">
 	<MkSpacer :contentMax="700">
 		<div class="_gaps">
 			<MkInput v-model="title">
@@ -37,7 +36,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			</MkSpacer>
 		</div>
 	</template>
-</MkStickyContainer>
+</PageWithHeader>
 </template>
 
 <script lang="ts" setup>