fix(multiplayer): converge events through REST

Game/scripts/matchmaking_state.gd

@@ -161,6 +161,19 @@ func apply_proposal_update(update: Dictionary) -> bool:
 	return true
 
 
+func prepare_proposal_recovery(new_proposal_id: String) -> bool:
+	if not _valid_opaque_id(new_proposal_id):
+		return false
+	if proposal_id == new_proposal_id:
+		return true
+	if proposal_state not in ["", "DECLINED", "EXPIRED", "CANCELLED"]:
+		return false
+	proposal_id = new_proposal_id
+	proposal_revision = 0
+	proposal_state = ""
+	return true
+
+
 func mark_assignment_ready() -> void:
 	phase = ASSIGNMENT_READY
 	message = "Match server is ready"