When viewing a specific version of a v2 library "problem" component, cannot submit answers

[bradenmacdonald]

When using the confirmation modal from #35669 , problem components cannot be tested (you can't try submitting an answer and seeing the result).

The reason is that the (frontend?) is incorrectly generating the handler URL if the "base" handler URL already has a query string:

Internal Server Error: /api/xblock/v2/xblocks/lb:OpenCraftX:ALPHA:problem:0166d443-bf7f-47f3-9f59-e208413600dc/handler/4-00c1a5e794d4da179d7f/xmodule_handler/?version=published/problem_check

Invalid version specifier 'published/problem_check'. Expected 'draft', 'published', or an integer.

[bradenmacdonald]

I have started working on a fix: #35676