fix: preserve active matchmaking on transient errors

Game/scripts/matchmaking_state.gd

@@ -68,6 +68,8 @@ func apply_ticket_update(update: Dictionary) -> bool:
 		expires_at_unix = int(update["expires_at_unix"])
 	if update.has("message"):
 		message = String(update["message"])
+	else:
+		message = ""
 	_emit_changed()
 	return true
 
@@ -104,6 +106,8 @@ func apply_proposal_update(update: Dictionary) -> bool:
 		return _request_resync(proposal_id)
 	proposal_revision = incoming_revision
 	proposal_state = incoming_proposal_state
+	if incoming_proposal_state == "OPEN" or incoming_proposal_state == "ACCEPTED":
+		message = ""
 	if update.has("expires_at_unix"):
 		expires_at_unix = int(update["expires_at_unix"])
 	_emit_changed()
@@ -134,6 +138,11 @@ func fail(reason: String) -> void:
 	_emit_changed()
 
 
+func set_notice(notice: String) -> void:
+	message = notice
+	_emit_changed()
+
+
 func can_cancel() -> bool:
 	return phase == QUEUED or phase == PROPOSED or phase == ALLOCATING