feat: 自由容器增加背景视频

app/web/page/activity/component/FreedomContainer/index.vue

 <template>
   <div class="freedom" v-track="{ link }">
     <div class="freedom-body">
+      <video width="100%" ref="videoBackground" height="auto" style="z-index: -10; osition: absolute; top: 0; left: 0" v-if="childItem.props.freedomVideo" :src="childItem.props.freedomVideo" autoplay loop muted />
       <component :class="['freedom-body-item', { 'Fb-item_selected': curChildIndex === index }]" v-for="(item, index) in childItem.child" :style="transformStyle(item.commonStyle, 'container')" :is="item.name" :key="index" :sa-info="getSaInfo(item)" v-bind="item.props"></component>
     </div>
   </div>