keyword search without javascript enabled results in a 500 error

[rlskoeser]

Describe the bug
Submitting a keyword search on the archive page with javascript disabled results in a 500 error

To reproduce
Steps to reproduce the behavior:

1. Turn off javascript in your browser
2. Go to https://prosody.princeton.edu/archive/
3. Type a keyword search term and hit enter to submit the search
4. See 500 error page

I'm using the Firefox noscript plugin; I gave permission for the things that are listed in the plugin and the page looks fine, but obviously something is not loading properly.

Expected behavior
Search should work even with javascript disabled.

Additional context
Error logs in the server indicate a sort option is not getting set:

    ArchiveSearchQuerySet()
  File "/var/www/ppa/env/lib/python3.9/site-packages/parasolr/query/aliased_queryset.py", line 86, in order_by
    return super().order_by(*args)
  File "/var/www/ppa/env/lib/python3.9/site-packages/parasolr/query/queryset.py", line 508, in order_by
    if sort_option.startswith("-"):
AttributeError: 'NoneType' object has no attribute 'startswith'

A default value should be set server-side if none is submitted (which is what seems to happen in this case).

Likely related problem: the sort option drop-down is not functional without javascript.