Set API Users table to vertical_on_small_screen

Using the app's new version of the Table component, this lays the
table's contents out vertically on screens tablet-sized and below.

In the related controller test, I've switched to using a regexp instead
of a string to match the contents of the table cells. The implementation
of `vertical_on_small_screen` embeds some markup in each table cell,
which would break these strict matchers.

app/views/api_users/index.html.erb

@@ -7,10 +7,11 @@
   } %>
 </div>
 
-<%= render "govuk_publishing_components/components/table", {
+<%= render "components/table", {
   caption: "API users",
   caption_classes: "govuk-visually-hidden",
   filterable: true,
+  vertical_on_small_screen: true,
   label: "Filter API users",
   head: [
     {

test/controllers/api_users_controller_test.rb

@@ -30,13 +30,13 @@ class ApiUsersControllerTest < ActionController::TestCase
       should "list api users" do
         create(:api_user, email: "api_user@email.com")
         get :index
-        assert_select "td", "api_user@email.com"
+        assert_select "td", /api_user@email.com/
       end
 
       should "not list web users" do
         create(:user, email: "web_user@email.com")
         get :index
-        assert_select "td", count: 0, text: "web_user@email.com"
+        assert_select "td", count: 0, text: /web_user@email.com/
       end
     end