unpinChatMessage method
Use this method to remove a message from the list of pinned messages in a chat.
If the chat is not a private chat, the bot must be an administrator in the chat for this to work and must have the 'can_pin_messages' admin right in a supergroup or 'can_edit_messages' admin right in a channel.
Returns True on success.
Implementation
Future<bool> unpinChatMessage(ChatID chatId, {int? messageId}) {
return _client.apiCall(_token, 'unpinChatMessage', {
'chat_id': chatId,
'message_id': messageId,
});
}