Fix search page history stack

[ChristopherChudzicki]

What are the relevant tickets?

Closes https://github.com/mitodl/hq/issues/5735

Description (What does it do?)

This PR changes setSearchParams to:

• add to the history stack correctly
• be purely client side

See associated @mitodl/course-search-utils PR for more.

How can this be tested?

1. On this branch, yarn install and restart the frontend
2. Visit the search interfaces, both /search and channel search /c/unit/ocw (etc). Things to check:
   1. Clicking facets adds to the history stack (press browser back/forward button)
   2. Appropriate API calls are made to server
   3. No text/x-component requests to the NextJS server (except maybe on initial load, but definitely not when clicking facets or submitting search text)

Checklist:

• First merge THIS_PR_RIGHT_HERE and use a published version

[ChristopherChudzicki]

🙏 for a more official mock app router ...