Vertical center the checkboxes

Changes

• Vertical center the checkboxes
• Side effect: may increase vertical margin

Currently, if I see closely, the checkbox label is placed slightly lower. This could be more clearer when I switched the language to Chinese, which has mostly square-shaped characters. This merge request tries to fix that.

Before

English	Chinese

After

English	Chinese

src/components/announcement_editor/announcement_editor.vue

@@ -32,8 +32,9 @@
         id="announcement-all-day"
         v-model="announcement.allDay"
         :disabled="disabled"
-      />
-      <label for="announcement-all-day">{{ $t('announcements.all_day_prompt') }}</label>
+      >
+        {{ $t('announcements.all_day_prompt') }}
+      </Checkbox>
     </span>
   </div>
 </template>