Improve launch error if wrong LTI version is used

This morning there was a temporary issue in our Canvas environment where assignments in a course using a course-level LTI 1.1 installation of Hypothesis failed to launch, due to Canvas using the wrong LTI protocol (LTI v1.3 instead of 1.1) to launch them. This happened due to our LTI 1.3 app being installed at the instance level ([Slack thread](https://hypothes-is.slack.com/archives/C4K6M7P5E/p1657086776817789)), causing Canvas to use LTI 1.3 for all LTI launches using the same domain.

The error shown on launch had no useful information about what the problem was:

Can we display a more informative error message in this scenario, so that IT admins, support staff etc. can diagnose the problem more easily?