chore(llm): change llm.auth.allow_override option default value to false

[oowl]

Summary

Checklist

• The Pull Request has tests
• A changelog file has been created under changelog/unreleased/kong or skip-changelog label added on PR if changelog is unnecessary. README.md
• There is a user-facing docs PR against https://github.com/Kong/docs.konghq.com - PUT DOCS PR HERE

Issue reference

Fix #[issue number]

[team-gateway-bot]

Cherry-pick failed for master, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally.

git remote add upstream https://github.com/kong/kong-ee
git fetch upstream master
git worktree add -d .worktree/cherry-pick-13505-to-master-to-upstream upstream/master
cd .worktree/cherry-pick-13505-to-master-to-upstream
git checkout -b cherry-pick-13505-to-master-to-upstream
ancref=$(git merge-base ca9c4ea8681062308b3a002c60e5f221e3d3f9a1 4701a4a8cf95d2c5c1b330ab794d66ff0e258204)
git cherry-pick -x $ancref..4701a4a8cf95d2c5c1b330ab794d66ff0e258204