message: chore(Sticky): avoid repeated observe
diff: import { inBrowser } from '../utils';
  -import {
  - Ref,
  - onMounted,
  - onActivated,
  - onDeactivated,
  - onBeforeUnmount,
  -} from 'vue';
  +import { Ref, onDeactivated, onBeforeUnmount } from 'vue';
  +import { onMountedOrActivated } from '@vant/use';
  // @Experimental
  export function useVisibilityChange(
  @@ -37,8 +32,7 @@ export function useVisibilityChange(
  }
  };
  - onMounted(observe);
  - onActivated(observe);
  onDeactivated(unobserve);
  onBeforeUnmount(unobserve);
  + onMountedOrActivated(observe);
  }
  