Fix scrolling benchmark

Change-Id: Ifb43ab0ffe6e38b00d5aad63415fc8439534c112

benchmarks/src/main/java/com/google/samples/apps/nowinandroid/foryou/ScrollForYouFeedBenchmark.kt

@@ -50,6 +50,7 @@ class ScrollForYouFeedBenchmark {
         }
     ) {
         forYouWaitForContent()
+        forYouSelectTopics()
         forYouScrollFeedDownUp()
     }
 }