Merge pull request #21219 from Justin-ZS/fix/20756_2

fix(dataset): wrong area when dimension name is empty string

Author: Ovilia

src/chart/line/LineView.ts

@@ -132,7 +132,7 @@ function getStackedOnPoints(
     data: SeriesData,
     dataCoordInfo: ReturnType<typeof prepareDataCoordInfo>
 ) {
-    if (!dataCoordInfo.valueDim) {
+    if (dataCoordInfo.valueDim == null) {
         return [];
     }