Import content pack failures

Bugfixes

• Importing a large content pack, for example the new Teams content pack on the marketplace, resulted in a failure.
• An imported exercise could not be added to a course while the exercise was available in the tenant.
• A hidden imported instruction was still visible for editors while adding instructions to a course.
• The REST API responded with a 500 status code when a 400 status code was expected.
• The default ordering of search results was not according to the design