chore(tests): replace deprecated BeautifulSoup findAll with find_all

[RayBB]

Switches from the deprecated method to in the home template tests, eliminating BeautifulSoup noise in test output.

[RayBB]

@Sanket17052006 can you give a review of this PR? It's a small one but fixes a little noise.

[Sanket17052006]

BeautifulSoup's findAll gives a DeprecationWarning: Call to deprecated method findAll. (Replaced by find_all) -- Deprecated since version 4.0.0. on every call. This PR removes that noise from pytest output. No functional change!

Ran docker compose run --rm home pytest openlibrary/plugins/openlibrary/tests/test_home.py -v

• master — 7 warnings (2 are findAll deprecation)
• PR branch — 5 warnings (findAll noise gone)

I ran rg "findAll" --type py across the repo and these 2 calls in test_home.py are the only findAll usages (the other 2 in vendor/infogami/ are vendored deps, out of scope)
LGTM!