[8.x] Deprecated authRequired in favor of security.authc.enabled (#202414) (#203531)

# Backport

This will backport the following commits from `main` to `8.x`:
- [Deprecated authRequired in favor of security.authc.enabled
(#202414)](https://github.com/elastic/kibana/pull/202414)

<!--- Backport version: 9.4.3 -->

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

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authRequired in favor of security.authc.enabled (#202414)\n\n##
Summary\r\n\r\nDeprecated `authRequired` in favor of
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[x]\r\n[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)\r\nwas
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BACKPORT-->

Co-authored-by: Elena Shostak <165678770+elena-shostak@users.noreply.github.com>

legacy_rfcs/text/0005_route_handler.md

@@ -45,7 +45,6 @@ interface KibanaRequest {
     path: string;
     method: 'get' | 'post' | ...
     options: {
-      authRequired: boolean;
       tags: string [];
     }
   }