MQE-1870: AllureHelper exception in suites

- AllureHelper checks storage before firing off event
- Small bugfix to static-checks

Author: KevinBKozan

src/Magento/FunctionalTestingFramework/Allure/AllureHelper.php

@@ -34,6 +34,11 @@ public static function addAttachmentToLastStep($data, $caption)
         $rootStep = Allure::lifecycle()->getStepStorage()->getLast();
         $trueLastStep = array_last($rootStep->getSteps());
 
+        if ($trueLastStep == null) {
+            // Nothing to attach to; do not fire off allure event
+            return;
+        }
+
         $attachmentEvent = new AddAttachmentEvent($data, $caption);
         $attachmentEvent->process($trueLastStep);
     }

src/Magento/FunctionalTestingFramework/StaticCheck/TestDependencyCheck.php

@@ -66,7 +66,7 @@ class TestDependencyCheck implements StaticCheckInterface
      * Array containing all errors found after running the execute() function.
      * @var array
      */
-    private $errors;
+    private $errors = [];
 
     /**
      * String representing the output summary found after running the execute() function.