Improve persistence of document search button state

[vkbo]

Summary:

This PR drops the local caching of the document search options in the search widget class and instead relies on the config settings everywhere they're accessed, and lets the toggle buttons set the configs directly.

Related Issue(s):

Closes #1794

Reviewer's Checklist:

• The header of all files contain a reference to the repository license
• The overall test coverage is increased or remains the same as before
• All tests are passing
• All flake8 checks are passing and the style guide is followed
• Documentation (as docstrings) is complete and understandable
• Only files that have been actively changed are committed