unpinChatMessage
Use this method to remove a message from the list of pinned messages in a chat. In private chats and channel direct messages chats, all messages can be unpinned. Conversely, the bot must be an administrator with the 'can_pin_messages' right or the 'can_edit_messages' right to unpin messages in groups and channels respectively. Returns True on success.
Parameters
businessConnectionId
Unique identifier of the business connection on behalf of which the message will be unpinned
chatId
Unique identifier for the target chat or username of the target channel (in the format @channelusername)
messageId
Identifier of the message to unpin. Required if business_connection_id is specified. If not specified, the most recent pinned message (by sending date) will be unpinned.