fix: chain backend should not be used for ultra light nodes (#5310)

Author: martinconic

pkg/node/node.go

@@ -500,17 +500,19 @@ func NewBee(
 		b.apiCloser = apiServer
 	}
 
-	// Sync the with the given Ethereum backend:
-	isSynced, _, err := transaction.IsSynced(ctx, chainBackend, maxDelay)
-	if err != nil {
-		return nil, fmt.Errorf("is synced: %w", err)
-	}
-	if !isSynced {
-		logger.Info("waiting to sync with the blockchain backend")
-
-		err := transaction.WaitSynced(ctx, logger, chainBackend, maxDelay)
+	if chainEnabled {
+		// Sync the with the given Ethereum backend:
+		isSynced, _, err := transaction.IsSynced(ctx, chainBackend, maxDelay)
 		if err != nil {
-			return nil, fmt.Errorf("waiting backend sync: %w", err)
+			return nil, fmt.Errorf("is synced: %w", err)
+		}
+		if !isSynced {
+			logger.Info("waiting to sync with the blockchain backend")
+
+			err := transaction.WaitSynced(ctx, logger, chainBackend, maxDelay)
+			if err != nil {
+				return nil, fmt.Errorf("waiting backend sync: %w", err)
+			}
 		}
 	}