Fix empty transaction point error

apps/api/src/app/portfolio/portfolio-calculator.ts

@@ -669,6 +669,7 @@ export class PortfolioCalculator {
     currencies: { [symbol: string]: string },
     symbols: { [symbol: string]: boolean }
   ) {
+    if (transactionPointsBeforeEndDate.length > 0) {
       for (const item of transactionPointsBeforeEndDate[firstIndex - 1].items) {
         dataGatheringItems.push({
           dataSource: item.dataSource,
@@ -678,6 +679,7 @@ export class PortfolioCalculator {
         symbols[item.symbol] = true;
       }
     }
+  }
 
   private getRelevantStartAndEndDates(
     start: Date,