update evaluation set size on sortedDataSelection

Author: bmschmidt

src/selection.ts

@@ -1064,6 +1064,10 @@ export class SortedDataSelection extends DataSelection {
     );
     newer.tiles = await Promise.all(withSort);
     newer.selectionSize = newer.tiles.reduce((sum, t) => sum + t.matchCount, 0);
+    newer.evaluationSetSize = newer.tiles.reduce(
+      (sum, t) => sum + t.tile.metadata.nPoints,
+      0,
+    );
     return newer;
   }
   // In addition to the regular things, we also need to add sort fields.