Extend XXE lesson with example where a mitigation of static analysis does not work

[nbaars]

I have an example in one of the presentations, we should add it to the documentation to make XXE more complete

[rajverma24]

SimpleXXETest.workingAttack:61 JSON path "$.feedback"
Expected: is "Congratulations. You have successfully completed the assignment."
but: was "Sorry the solution is not correct, please try again."

[rajverma24]

Guys, I’m not sure if this is my personal problem or the same issues facing all of them
[ERROR] Failures:
[ERROR] ContentTypeAssignmentTest.workingAttack:78 JSON path "$.feedback"
Expected: is "Congratulations. You have successfully completed the assignment."
but: was "Sorry the solution is not correct, please try again."
[ERROR] SimpleXXETest.workingAttack:61 JSON path "$.feedback"
Expected: is "Congratulations. You have successfully completed the assignment."
but: was "Sorry the solution is not correct, please try again."
[INFO]
[ERROR] Tests run: 242, Failures: 2, Errors: 0, Skipped: 2
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE