Additional cleanify changes to ls2ls integ tests (#17246)

* Additional cleanify changes to ls2ls integ tests: replace heartbeat-input with reload option, set queue drain to get consistent result.

(cherry picked from commit 1e06eea)

Author: mashhurs

qa/integration/fixtures/persistent_queues/logstash.yml

@@ -1 +1,2 @@
 queue.type: persisted
+queue.drain: true

qa/integration/specs/logstash_to_logstash_spec.rb

@@ -53,7 +53,8 @@ def run_logstash_instance(config_name, options = {}, &block)
                                     "--pipeline.id", config_name,
                                     "--path.config", config_to_temp_file(@fixture.config(config_name, options)),
                                     "--path.data", get_temp_path_dir,
-                                    "--api.http.port", api_port.to_s)
+                                    "--api.http.port", api_port.to_s,
+                                    "--config.reload.automatic")
     logstash_service.wait_for_rest_api
     yield logstash_service
   ensure