[DOCS] Add tip for Kibana anonymous authentication (elastic#73858)

You shouldn't use Elasticsearch's anonymous access to provide access to Kibana
without requiring credentials. Instead, you should use Kibana's anonymous
authentication feature. However, the Elasticsearch anonymous access tends to be
more popular in search results.

This adds a brief tip that directs users to Kibana's anonymous authentication
feature.

Closes elastic#73022

Author: jrodewig

x-pack/docs/en/security/authentication/anonymous-access.asciidoc

@@ -2,6 +2,11 @@
 [[anonymous-access]]
 === Enabling anonymous access
 
+TIP: To embed {kib} dashboards or grant access to {kib} without requiring
+credentials, use {kib}'s
+{kibana-ref}/kibana-authentication.html#anonymous-authentication[anonymous
+authentication] feature instead.
+
 Incoming requests are considered to be _anonymous_ if no authentication token 
 can be extracted from the incoming request. By default, anonymous requests are rejected and an authentication error is returned (status code `401`).