fix: detecting group creation message

[missytake]

Depending on the core and team-bot version when the chat was created, the group creation message can be in a different position and have different wording. Iterating through legacy wordings as well, through the first three messages, should be enough to catch it.

The current behavior leads to failing messages with the following traceback:

Traceback (most recent call last):                                                                   
  File "/home/das_synthikat/.local/lib/team-bot.venv/lib/python3.11/site-packages/deltachat_rpc_client/client.py", line 136, in _on_event                                  
    hook(event)                                                                       
  File "/home/das_synthikat/.local/lib/team-bot.venv/lib/python3.11/site-packages/team_bot/relay.py", line 98, in incoming_message                                         
    handle_msg_in_relay_group(msg)                                                                   
  File "/home/das_synthikat/.local/lib/team-bot.venv/lib/python3.11/site-packages/team_bot/relay.py", line 176, in handle_msg_in_relay_group                               
    forward_to_outside(msg)                                                                   
  File "/home/das_synthikat/.local/lib/team-bot.venv/lib/python3.11/site-packages/team_bot/forwarding.py", line 55, in forward_to_outside                                  
    raise e                                                                   
  File "/home/das_synthikat/.local/lib/team-bot.venv/lib/python3.11/site-packages/team_bot/forwarding.py", line 38, in forward_to_outside                                  
    if msg.quote.message_id == get_group_creation_msg(msg.chat).id:                                                                                                        
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                                                        
  File "/home/das_synthikat/.local/lib/team-bot.venv/lib/python3.11/site-packages/team_bot/util.py", line 71, in get_group_creation_msg                                    
    assert msgs[1].get_snapshot().text[:20] in ["This is a chat with ", "We sent a message to"]                                                                       
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError