[chore] remove example (#45964)

Remove the example of the splunkhecexporter.

Author: atoulme

Makefile

@@ -589,7 +589,6 @@ otel-from-lib:
 .PHONY: build-examples
 build-examples:
 	cd examples/secure-tracing/certs && $(MAKE) clean && $(MAKE) all && docker compose -f ../docker-compose.yaml build
-	docker compose -f exporter/splunkhecexporter/example/docker-compose.yml build
 
 .PHONY: deb-rpm-package
 %-package: ARCH ?= amd64