UI to select components for the Problem Bank (MVP)

[bradenmacdonald]

Note: "Problem Bank" is in the UI, ItemBankBlock is what it's called in the backend.

Building on openedx/edx-platform#35553 (backend PR) and #1356 (add library component picker), integrate the component picker into the UI for the Problem Bank editor, so that authors can:

1. Create a Problem Bank in the course
2. Select a library and then one or more components using the component picker (ideally it should allow multiple selections at once - see Figma designs; I recommend doing that as a separate follow-up PR to reduce risk)
   • Also note the multi-select UI is almost identical to what we need for Collections Page - Add existing content from within a collection #1173
3. See those components in the course (as children of the Problem Bank).
   • They should be "linked" and display the library icon (and sync button if updates are available) - but no specific work needs to be done for that; it should be already implemented. The only thing necessary here is to use the correct APIs to copy the blocks into the course as linked content.

This is an MVP version so the UI can be as bare-bones as necessary. But the workflow should be working end to end.

[bradenmacdonald]

@jmakowski1123 Another new ticket to check please.