docs: fix links (elastic#115642) (elastic#115679)

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

docs/apm/agent-configuration.asciidoc

@@ -25,7 +25,7 @@ For this reason, it is still important to set custom default configurations loca
 [float]
 ==== APM Server setup
 
-This feature requires https://www.elastic.co/guide/en/apm/server/master/setup-kibana-endpoint.html[Kibana endpoint configuration] in APM Server.
+This feature requires {apm-server-ref-v}/setup-kibana-endpoint.html[Kibana endpoint configuration] in APM Server.
 
 Why is additional configuration needed in APM Server?
 That's because APM Server acts as a proxy between the agents and Kibana.