[Monitoring] ProductNotSupportedError coming from monitoring bulk api

[liza-mae]

Kibana version: 8.x

Elasticsearch version: 8.x

Server OS version: Cloud

Original install method (e.g. download page, yum, from source, etc.): Cloud

Describe the bug: During some automated test runs, the tests began to fail and looking at the logs the following error was repeating bunch of times. ProductNotSupportedError: The client noticed that the server is not Elasticsearch and we do not support this unknown product

Steps to reproduce: It is not clear yet how to reproduce this, as subsequent automaton runs did not show the problem. Slack conversation: https://elastic.slack.com/archives/C9097ABGC/p1644357582508429 cc: @delvedor

Provide logs and/or server output (if relevant):

ProductNotSupportedError: The client noticed that the server is not Elasticsearch and we do not support this unknown product.
    at KibanaTransport.request (/usr/share/kibana/node_modules/@elastic/transport/lib/Transport.js:403:27)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at KibanaTransport.request (/usr/share/kibana/src/core/server/elasticsearch/client/create_transport.js:63:16)
    at Monitoring.bulk (/usr/share/kibana/node_modules/@elastic/elasticsearch/lib/api/api/monitoring.js:53:16)
    at sendBulkPayload (/usr/share/kibana/x-pack/plugins/monitoring/server/kibana_monitoring/lib/send_bulk_payload.js:24:7)
    at BulkUploader._onPayload (/usr/share/kibana/x-pack/plugins/monitoring/server/kibana_monitoring/bulk_uploader.js:188:12)
    at BulkUploader._fetchAndUpload (/usr/share/kibana/x-pack/plugins/monitoring/server/kibana_monitoring/bulk_uploader.js:174:9)

[elasticmachine]

Pinging @elastic/infra-monitoring-ui (Team:Infra Monitoring UI)

[liza-mae]

This was seen again in testing, needs to be looked at by the monitoring team.

https://internal-ci.elastic.co/view/Stack%20Tests/job/elastic+estf-cloud-kibana-tests/2928/