refactor: adapt page header styles for responsive design (#7544)

#### What type of PR is this?

/area ui
/kind improvement
/milestone 2.21.x

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

Adapt page header styles for responsive design

before:

<img width="415" alt="image" src="https://github.com/user-attachments/assets/feee6f09-9a77-4bbf-94c2-77725c9ce76b" />

after:

<img width="416" alt="image" src="https://github.com/user-attachments/assets/60bb07a3-5d34-4cf6-b103-5d1f2206d62d" />

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

Fixes https://github.com/halo-dev/halo/issues/6425

#### Special notes for your reviewer:

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

```release-note
优化移动端下文章编辑页面的样式
```

ui/console-src/modules/dashboard/Dashboard.vue

@@ -35,7 +35,7 @@ provide<ComputedRef<DashboardWidgetDefinition[]>>(
 <template>
   <VPageHeader :title="$t('core.dashboard.title')">
     <template #icon>
-      <IconDashboard class="mr-2 self-center" />
+      <IconDashboard />
     </template>
     <template #actions>
       <VButton