[7.17] [Docs] Adds authentication providers sync to load balancing documentation (#149961) (#150192)

# Backport

This will backport the following commits from `main` to `7.17`:
- [[Docs] Adds authentication providers sync to load balancing
documentation (#149961)](https://github.com/elastic/kibana/pull/149961)

<!--- Backport version: 8.9.7 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Jeramy
Soucy","email":"jeramy.soucy@elastic.co"},"sourceCommit":{"committedDate":"2023-02-02T16:11:35Z","message":"[Docs]
Adds authentication providers sync to load balancing documentation
(#149961)\n\nCloses #113928\r\n\r\n## Summary\r\n\r\n- Adds
'xpack.security.authc.providers' to the list of settings that\r\nmust be
the same across all Kibana instances behind a load balancer.\r\n- Adds a
warning block explaining why the authentication providers need\r\nto
match, and an additional configuration case where this
applies\r\n(Kibana instances that are backed by the same ES instance and
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Adds authentication providers sync to load balancing documentation
(#149961)\n\nCloses #113928\r\n\r\n## Summary\r\n\r\n- Adds
'xpack.security.authc.providers' to the list of settings that\r\nmust be
the same across all Kibana instances behind a load balancer.\r\n- Adds a
warning block explaining why the authentication providers need\r\nto
match, and an additional configuration case where this
applies\r\n(Kibana instances that are backed by the same ES instance and
share the\r\nsame
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Adds authentication providers sync to load balancing documentation
(#149961)\n\nCloses #113928\r\n\r\n## Summary\r\n\r\n- Adds
'xpack.security.authc.providers' to the list of settings that\r\nmust be
the same across all Kibana instances behind a load balancer.\r\n- Adds a
warning block explaining why the authentication providers need\r\nto
match, and an additional configuration case where this
applies\r\n(Kibana instances that are backed by the same ES instance and
share the\r\nsame
kibana.index).","sha":"1418d753eacd0095cca4f08af5c5b12cc9af0817"}}]}]
BACKPORT-->

Co-authored-by: Jeramy Soucy <jeramy.soucy@elastic.co>

docs/user/production-considerations/production.asciidoc

@@ -42,11 +42,18 @@ These settings must be the same:
 [source,js]
 --------
 xpack.security.encryptionKey //decrypting session information
+xpack.security.authc.* // authentication configuration
+xpack.security.session.* // session configuration
 xpack.reporting.encryptionKey //decrypting reports
 xpack.encryptedSavedObjects.encryptionKey // decrypting saved objects
 xpack.encryptedSavedObjects.keyRotation.decryptionOnlyKeys // saved objects encryption key rotation, if any
 --------
 
+[WARNING]
+====
+If the authentication configuration does not match, sessions from unrecognized providers in each {kib} instance will be deleted during that instance's regular session cleanup. Similarly, inconsistencies in session configuration can also lead to undesired session logouts. This also applies to any {kib} instances that are backed by the same {es} instance and share the same kibana.index, even if they are not behind the same load balancer.
+====
+
 Separate configuration files can be used from the command line by using the `-c` flag:
 [source,js]
 --------