FIX: reverts #18e2816 (#7940)

test/javascripts/acceptance/topic-test.js.es6

@@ -255,13 +255,6 @@ QUnit.test("selecting posts", async assert => {
     exists(".select-all"),
     "it should allow users to select all the posts"
   );
-
-  await click(".toggle-admin-menu");
-
-  assert.ok(
-    exists(".selected-posts.hidden"),
-    "it should hide the multi select menu"
-  );
 });
 
 QUnit.test("select below", async assert => {