Remove redundant APM agent configuration API page

Author: lcawl

solutions/observability/apps/agent-configuration-api.md

@@ -1,13 +1,16 @@
 ---
 mapped_pages:
   - https://www.elastic.co/guide/en/observability/current/apm-app-api.html
+applies_to:
+  stack: all
+  serverless: all
 ---
 
 # APM UI API [apm-app-api]
 
 Some Applications UI features are provided via a REST API:
 
-* [Agent Configuration API](agent-configuration-api.md)
+* Agent Configuration API ([{{stack}}](https://www.elastic.co/docs/api/doc/kibana/group/endpoint-apm-agent-configuration) or [{{serverless-short}}](https://www.elastic.co/docs/api/doc/serverless/group/endpoint-apm-agent-configuration))
 * [Annotation API](annotation-api.md)
 * [RUM source map API](rum-source-map-api.md)
 * [APM agent Key API](apm-agent-key-api.md)

solutions/observability/apps/apm-ui-api.md

@@ -174,7 +174,7 @@ The transaction sample rate can be changed dynamically (no redeployment necessar
 
 ### {{kib}} API configuration [_kib_api_configuration]
 
-{{apm-agent}} configuration exposes an API that can be used to programmatically change your agents' sampling rate. An example is provided in the [Agent configuration API reference](../../../solutions/observability/apps/agent-configuration-api.md).
+{{apm-agent}} configuration exposes an API that can be used to programmatically change your agents' sampling rate. For examples, refer to the [Agent configuration API reference](https://www.elastic.co/docs/api/doc/kibana/group/endpoint-apm-agent-configuration).
 
 
 ### {{apm-agent}} configuration [_apm_agent_configuration]

solutions/observability/apps/transaction-sampling.md

@@ -165,7 +165,6 @@ toc:
                 children:
                   - file: observability/apps/apm-ui-api.md
                     children:
-                      - file: observability/apps/agent-configuration-api.md
                       - file: observability/apps/annotation-api.md
                       - file: observability/apps/rum-source-map-api.md
                       - file: observability/apps/apm-agent-key-api.md