Firehose agentless integration

### Before you submit

- [x] This issue is about a documentation page, flow, or piece of content.

### Type of issue

I can't find what I'm looking for

### What documentation page or section is affected

https://www.elastic.co/docs/solutions/observability/cloud/monitor-amazon-web-services-aws-with-amazon-data-firehose

### What happened?

Hi Team - The documentation does not mention that the AWS Data Firehose integration is agentless and does not require an Elastic Agent.
Additionally, the integration does not appear in Kibana Integrations when the “Only agentless integrations” filter is enabled.

KB article - https://support.elastic.co/knowledge/8547c3de

### Additional info

_No response_