[Docs] Update feature privilege docs to reflect new route authorizati…

…on (elastic#201017)

## Summary

Updates developer documentation on Feature privileges to reflect changes
to Route Authorization.


### Screenshots
Before
<img width="400" alt="Screenshot 2024-11-20 at 18 52 02"
src="https://github.com/user-attachments/assets/0bb01bd0-e41a-48ee-bcaf-bd4119037f1b">

After
<img width="400" alt="Screenshot 2024-11-20 at 18 49 26"
src="https://github.com/user-attachments/assets/2d5712ce-c277-4ecd-831e-750df8309933">


### Checklist

Check the PR satisfies following conditions. 

Reviewers should verify this PR satisfies this list as well.

- [x]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials

dev_docs/key_concepts/feature_privileges.mdx

@@ -179,8 +179,10 @@ public setup(core: CoreSetup, deps: FeatureControlExampleDeps) {
       {
         path: '/internal/my_plugin/sensitive_action',
         validate: false,
-        options: {
-          tags: ['access:my_closed_example_api'],
+        security: {
+          authz: {
+            requiredPrivileges: ['my_closed_example_api']
+          }
         },
       },
       async (context, request, response) => {
@@ -193,8 +195,11 @@ public setup(core: CoreSetup, deps: FeatureControlExampleDeps) {
     );
 }
 ```
+<DocCallOut>
+  For more information on the `security.authz` object and API authorization, please refer to our guide on <DocLink id="kibDevDocsSecurityAPIAuthorization" text="Configuring authorization on routes"/>
+</DocCallOut>
 
-Notice, we've added an `options.tags` property for the API route that returns sensitive information. This tag is then used in the privileges object as follow
+Notice, we've added a `security.authz.requiredPrivileges` property for the API route that returns sensitive information. This added configuration is then used in the privileges object as follow
 
 ```ts
 {
@@ -347,7 +352,6 @@ A deep dive into every option for the Kibana Feature configuration and what they
   }
   ```
 
-
 ### FeatureKibanaPrivileges Interface
 
 #### excludeFromBasePrivileges (optional)