Fix only first page being loaded in PaginatedMultiSelect

[acelaya]

Part of https://github.com/hypothesis/support/issues/178
Depends on hypothesis/frontend-shared#1864

Use the fixes introduced in hypothesis/frontend-shared#1864 to ensure all pages are loaded in PaginatedMultiSelect as you scroll down.

Test steps

1. Go to https://hypothesis.instructure.com/courses/319/assignments and log in as instructor
2. Launch a "bunch" of localhost assignments from there, to build a relatively long list.
3. Go to http://localhost:8001/dashboard/courses/1. You should see all assignments you lunched listed there, and they should also show in the "Assignments" dropdown.
4. Apply this diff, which does two things: a) reduce the items per page returned by paginated API calls and b) reduce the size of Select popovers, so that scroll appears even with very few items on it.

   diff --git a/lms/static/scripts/frontend_apps/components/dashboard/PaginatedMultiSelect.tsx b/lms/static/scripts/frontend_apps/components/dashboard/PaginatedMultiSelect.tsx
   index 384219a3a..f5613e0b0 100644
   --- a/lms/static/scripts/frontend_apps/components/dashboard/PaginatedMultiSelect.tsx
   +++ b/lms/static/scripts/frontend_apps/components/dashboard/PaginatedMultiSelect.tsx
   @@ -98,6 +98,7 @@ export default function PaginatedMultiSelect<TResult, TSelect>({
          onChange={onChange}
          aria-label={`Select ${entity}`}
          containerClasses="!w-auto min-w-44"
   +      popoverClasses="!max-h-24"
          buttonContent={buttonContent}
          data-testid={`${entity}-select`}
          onPopoverScroll={e => {
   diff --git a/lms/views/dashboard/pagination.py b/lms/views/dashboard/pagination.py
   index 38325e270..a865d88f8 100644
   --- a/lms/views/dashboard/pagination.py
   +++ b/lms/views/dashboard/pagination.py
   @@ -15,7 +15,7 @@ LOG = logging.getLogger(__name__)
    T = TypeVar("T")
    
    
   -MAX_ITEMS_PER_PAGE = 100
   +MAX_ITEMS_PER_PAGE = 3
    """Maximum number of items to return in paginated endpoints"""

5. Open the assignments dropdown, which should only show three assignments. Scroll down and observe how new pages continue loading until all assignments are there.

In main, if you apply the same diff, you'll see how only the first page of assignments is loaded even if you scroll.

Warning

There's an unrelated issue with students when loaded from the the roster, where we seem to be returning the first page on every request, even when a cursor is provided.
This PR does not cover fixing that.

[robertknight]

Use the fixes introduced in hypothesis/frontend-shared#1864 to ensure all pages are loaded in PaginatedMultiSelect as you scroll down.

This PR just avoids the use of a deprecated API right? Any code that still uses the old prop will still get the fix.

[acelaya]

Use the fixes introduced in hypothesis/frontend-shared#1864 to ensure all pages are loaded in PaginatedMultiSelect as you scroll down.

This PR just avoids the use of a deprecated API right? Any code that still uses the old prop will still get the fix.

This PR is still missing the actual fix, which is updating to the latest version of frontend-shared.

I also took the opportunity to stop using the deprecated prop, but the fix would take effect even without that change.