PULL_REQUEST_TEMPLATE.md: add extra question on testing PR (#8035)

PR adds an extra question to the PR template.

Author: DaanHoogland

PULL_REQUEST_TEMPLATE.md

@@ -43,8 +43,12 @@ This PR...
 
 
 ### How Has This Been Tested?
+
 <!-- Please describe in detail how you tested your changes. -->
 <!-- Include details of your testing environment, and the tests you ran to -->
+
+#### How did you try to break this feature and the system with this change?
+
 <!-- see how your change affects other areas of the code, etc. -->