fix: address comments

Author: arjunlalb

projects/observability/src/shared/components/cartesian/cartesian-chart.component.ts

@@ -175,10 +175,7 @@ export class CartesianChartComponent<TData> implements OnChanges, OnDestroy {
         label: singleValue.context.name,
         value: defaultYDataAccessor<number | string>(singleValue.dataPoint),
         units: singleValue.context.units,
-        color:
-          singleValue.context.getColor !== undefined
-            ? singleValue.context.getColor(singleValue.dataPoint)
-            : singleValue.context.color
+        color: singleValue.context.getColor?.(singleValue.dataPoint) ?? singleValue.context.color
       }))
     };
   }

projects/observability/src/shared/components/cartesian/d3/data/series/cartesian-column.ts

@@ -43,7 +43,7 @@ export class CartesianColumn<TData> extends CartesianSeries<TData> {
   }
 
   private getColorForDatum(datum: TData): string {
-    return this.series.getColor ? this.series.getColor(datum) : this.series.color;
+    return this.series.getColor?.(datum) ?? this.series.color;
   }
 
   protected buildMultiAxisDataLookupStrategy(): MouseDataLookupStrategy<TData, Series<TData>> {