docs(tutorial): add missing beforeEach(module()) to test

Test snippet was missing this necessary statement that was present in the sample code.

Closes #5743

docs/content/tutorial/step_05.ngdoc

@@ -170,6 +170,9 @@ describe('PhoneCat controllers', function() {
   describe('PhoneListCtrl', function(){
     var scope, ctrl, $httpBackend;
 
+    // Load our app module definition before each test.
+    beforeEach(module('phonecatApp'));
+
     // The injector ignores leading and trailing underscores here (i.e. _$httpBackend_).
     // This allows us to inject a service but then attach it to a variable
     // with the same name as the service.