Show a message if joining via clonk://-url fails

[Somebodyisnobody]

It is confusing for the user if he wants to join an outdated reference with clonk (clonk.exe clonk://league.clonkspot.org:80/?action=query&game_id=1234567) and the game closes immediately because no active reference with this ID was found.
The user only sees a black screen and a flickering loading screen for a short time.

A message should be displayed that the reference was not found. This must be confirmed with "OK" before the game closes.

[Fulgen301]

That breaks starting games via command line without user interaction. Time for the n+1th command line argument, I guess...

[Somebodyisnobody]

I am okay with a timer which automatically closes the game after n seconds idle or a command to suppress any errors like -q or something else.