Added fleet-server known issue 7.17.20

[juliaElastic]

Preview: https://ingest-docs_bk_1006.docs-preview.app.elstc.co/guide/en/fleet/7.17/release-notes-7.17.20.html

[juliaElastic]

Build fails with this issue:

INFO:build_docs:All cross-document links OK
INFO:build_docs:Saving branch tracker
INFO:build_docs:Building sitemap
INFO:build_docs:Commiting changes
INFO:build_docs:Pushing changes
INFO:build_docs:Error executing: git push origin ingest-docs_bk_1006 in GIT_DIR /docs_build/.repos/target_repo.git
INFO:build_docs:---out---
INFO:build_docs:
INFO:build_docs:---err---
INFO:build_docs:Failed to add the ECDSA host key for IP address '140.82.113.3' to the list of known hosts (/tmp/.ssh/known_hosts).
INFO:build_docs:To github.com:elastic/built-docs
INFO:build_docs: ! [rejected]                    ingest-docs_bk_1006 -> ingest-docs_bk_1006 (fetch first)
INFO:build_docs:error: failed to push some refs to 'git@github.com:elastic/built-docs'
INFO:build_docs:hint: Updates were rejected because the remote contains work that you do
INFO:build_docs:hint: not have locally. This is usually caused by another repository pushing
INFO:build_docs:hint: to the same ref. You may want to first integrate the remote changes
INFO:build_docs:hint: (e.g., 'git pull ...') before pushing again.
INFO:build_docs:hint: See the 'Note about fast-forwards' in 'git push --help' for details.
INFO:build_docs:
INFO:build_docs:---------
🚨 Error: The command exited with status 1
user command error: exit status 1

[jlind23]

Code change looks good to me.

[leemthompo]

@juliaElastic CI is now green after rebuild :)

[kilfoyle]

LGTM! Just two small suggestions.
Thanks for adding this @juliaElastic!

[juliaElastic]

Thanks @kilfoyle for the review! I added some more details that the issue impacts ESS too, as discussed with Julien and the team.