fix(multiplayer): recover requeued tickets

Game/scripts/matchmaking_state.gd

@@ -217,6 +217,10 @@ func can_cancel() -> bool:
 	return phase == QUEUED or phase == PROPOSED or phase == ALLOCATING
 
 
+func has_open_proposal() -> bool:
+	return not proposal_id.is_empty() and proposal_state == "OPEN"
+
+
 func waited_seconds(now_unix: int) -> int:
 	if enqueued_at_unix <= 0:
 		return 0