Fix for test-data make target (#18229)

* Fix for the test-data command.

* Sleep and warn about needing local mode enabled.

* Improved server start synchro.

Makefile

@@ -425,9 +425,15 @@ cover: ## Runs the golang coverage tool. You must run the unit tests first.
 	$(GO) tool cover -html=cover.out
 	$(GO) tool cover -html=ecover.out
 
-test-data: start-docker ## Add test data to the local instance.
-	$(GO) run $(GOFLAGS) -ldflags '$(LDFLAGS)' $(PLATFORM_FILES) config set TeamSettings.MaxUsersPerTeam 100
-	$(GO) run $(GOFLAGS) -ldflags '$(LDFLAGS)' $(PLATFORM_FILES) sampledata -w 4 -u 60
+test-data: run-server ## Add test data to the local instance.
+	@if ! ./scripts/wait-for-system-start.sh; then \
+		make stop; \
+	fi
+
+	@echo ServiceSettings.EnableLocalMode must be set to true.
+
+	bin/mmctl config set TeamSettings.MaxUsersPerTeam 100 --local
+	bin/mmctl sampledata -u 60 --local
 
 	@echo You may need to restart the Mattermost server before using the following
 	@echo ========================================================================