LTI: support substitution parameter for course history

In this test, we're going to create a course and copies of it, and verify the history of the course (i.e. the ancestor course ids) are passed to the test tool. pre-requisite LTI Advantage requires your site to be reachable from the internet. If not, Install ngrok to expose your moodle setup externally. Refer here for additional guidelines Have a course with an instructor. As admin install the LTI Robotest test app using the instructions found at https://robotest.theedtech.dev Make sure to set the custom parameters as indicated, in particular the $Context.id.history since it will be the one we will verify in this test. Tool configuration usage: Show in activity chooser and as preconfigured tool Enter a course as instructor Turn editing on Add external activity, choose Robotest app Click Select Content and Select one item (graded or not, does not matter) Save and Return to Course Verify Launch the newly added link to the test app and verify the $Context.id.history says it's blank Copy the course as a new course (copy, or backup and restore in new course) In that new course, click on the same link Verify the $Context.id.history is now a number (the id of the previous course) Copy this course as a new course again Verify the $Context.id.history is now 2 numbers separated by a comma, the highest number first