Function setConversationToTopInTag

setConversationToTopInTag(
    tagId: string,
    conversation: IConversationIdentifier,
    isTop: boolean,
): Promise<RCResult<void>>
设置标签中会话置顶
Parameters
- tagId: string
  标签 id
- conversation: IConversationIdentifier
  会话
- isTop: boolean
Returns Promise<RCResult<void>>
Description
设置在指定标签下置顶的会话。如果根据标签获取会话，可在获取的会话中可以看到该属性。请注意与会话列表中的会话置顶相区分
Example: 设置标签中会话置顶示例：
```
const tagId = 'tagId';
const conversation = {
 conversationType: RongIMLib.ConversationType.PRIVATE,
 targetId: 'targetId',
};
const isTop = true;
const res = await RongIMLib.setConversationToTopInTag(tagId, conversation, isTop);
console.log('设置标签中会话置顶结果：', res);
```