Update settings docs with new xpack.rollup and xpack.license_management settings.

[cjcenizal]

Follow-on to #30149.

[elasticmachine]

💔 Build Failed

• continuous-integration/kibana-ci/pull-request

[jen-huang]

LGTM!

Not related to this change: it's odd that we only list 2 plugins in this settings doc. We should consider adding all plugins in another doc enhancement 🙂

[lcawl]

Historically we've had separate settings pages for the commercial features (see https://www.elastic.co/guide/en/kibana/master/settings-xpack-kb.html)

If we want to continue that model, we'd have a separate page for the rollup feature and maybe one for licensing as well. @schersh I've actually been pondering how/if we could integrate the "X-Pack" settings more closely with the OSS ones, so we might want to consider taking this opportunity to talk about a better integration. I think there are way too many (especially where security is concerned) to merge them all into a single page, but I'd be interested to know if you would want them as sub-pages (for example as peers to the "Secure settings" page).

[cjcenizal]

@lcawl Thanks for taking a look. Those are good ideas. Can we pursue them in a separate issue? I believe we can merge this PR as-is (since we're not introducing anything new, just fixing an error) and then continue the discussion on how to improve the structure of these docs separately.

[cjcenizal]

This is a docs change, so I'm going to merge regardless of the red CI.