MM-60283 Add standard response and API docs to /client_perf API (#28124)

* MM-60283 Add standard response to /client_perf API

* Add API docs for /client_perf endpoint

* Fix invalid response schema

api/Makefile

@@ -56,6 +56,7 @@ build-v4: node_modules playbooks
 	@cat $(V4_SRC)/limits.yaml >> $(V4_YAML)
 	@cat $(V4_SRC)/logs.yaml >> $(V4_YAML)
 	@cat $(V4_SRC)/outgoing_oauth_connections.yaml >> $(V4_YAML)
+	@cat $(V4_SRC)/metrics.yaml >> $(V4_YAML)
 	@if [ -r $(PLAYBOOKS_SRC)/paths.yaml ]; then cat $(PLAYBOOKS_SRC)/paths.yaml >> $(V4_YAML); fi
 	@if [ -r $(PLAYBOOKS_SRC)/merged-definitions.yaml ]; then cat $(PLAYBOOKS_SRC)/merged-definitions.yaml >> $(V4_YAML); else cat $(V4_SRC)/definitions.yaml >> $(V4_YAML); fi
 	@echo Extracting code samples