Use WhereIn for experiment course grade aggregation

src/Jiaowu.Api/Controllers/ExperimentGradesController.cs

@@ -252,9 +252,8 @@ public sealed class ExperimentGradesController(
             .ToListAsync(cancellationToken);
         var taskIds = results.Select(x => x.TeachingTaskId).Distinct().ToArray();
         var aggregates = await db.ExperimentCourseGrades.AsNoTracking()
-            .Where(x =>
+            .Where(x => x.StudentId == student.Id)
-                x.StudentId == student.Id &&
+            .WhereIn(taskIds, x => x.TeachingTaskId)
-                taskIds.Contains(x.TeachingTaskId))
             .ToDictionaryAsync(x => x.TeachingTaskId, cancellationToken);
         var courses = results
             .GroupBy(x => x.TeachingTaskId)