"I left the group" message not sent due to encryption error but user is kicked from group

[adbenitez]

It happens some time that due to missing gossip, you can't send a message in a protected chat:

when this happens, core refuses to send your message, however, if you try to leave the group, even if core refused to proceed with your action, in your device, you are no longer a member of the group and can't try to send messages anymore

reverting this actions is a bit problematic for other cases like removing someone else of the group, since then ex. if you want to remove some peer with missing key/gossip, you will not be able to do it and could never talk again in the group, but at least when you try to leave yourself, it is safe to keep you in the group if the message will not be sent, for adding other members, it also makes sense to revert if message was canceled