Remove 'onFilteredOut' and 'onDroppedOnPublish' callback logs (#36399) (

#36487)

The 'onFilteredOut' and 'onDroppedOnPublish' callbacks debug logs can
cause an infinity loop of log entries being logged over and over again
when running under Elastic-Agent. Those log entries are removed to
prevent this from happening in the future.

The monitoring Filebeat uses a drop processor to drop its own logs,
however if log level is debug the `onFilteredOut` callback debug log
will log all dropped events, because it is done by the monitoring
Filebeat, it will be picked up, dropped and logged again, creating
this infinity loop.

(cherry picked from commit dde4079)

Co-authored-by: Tiago Queiroz <[email protected]>

CHANGELOG.next.asciidoc

@@ -101,6 +101,7 @@ https://github.com/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 - Remove erroneous error log in GCPPubSub input. {pull}36296[36296]
 - Fix Filebeat Cisco module with missing escape character {issue}36325[36325] {pull}36326[36326]
 - Fix panic when redact option is not provided to CEL input. {issue}36387[36387] {pull}36388[36388]
+- Remove 'onFilteredOut' and 'onDroppedOnPublish' callback logs {issue}36299[36299] {pull}36399[36399]
 
 *Heartbeat*
 

libbeat/publisher/pipeline/client.go

@@ -203,12 +203,10 @@ func (c *client) onPublished() {
 }
 
 func (c *client) onFilteredOut(e beat.Event) {
-	c.logger.Debugf("Pipeline client receives callback 'onFilteredOut' for event: %+v", e)
 	c.observer.filteredEvent()
 }
 
 func (c *client) onDroppedOnPublish(e beat.Event) {
-	c.logger.Debugf("Pipeline client receives callback 'onDroppedOnPublish' for event: %+v", e)
 	c.observer.failedPublishEvent()
 	if c.clientListener != nil {
 		c.clientListener.DroppedOnPublish(e)