Elastic Agent: replace agentbeat with elastic-otel-collector

[cmacknz]

Summary

In 9.3.0 we replaced the agentbeat executable with the elastic-otel-collector executable (which also implements the EDOT collector). Replace all references to agentbeat with elastic-otel-collector.

Generative AI disclosure

1. Did you use a generative AI (GenAI) tool to assist in creating this contribution?

• Yes
• No

[github-actions]

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[github-actions]

🔍 Preview links for changed docs

• reference/fleet/example-kubernetes-standalone-agent-helm.md
• reference/fleet/install-elastic-agents.md

[vishaangelova]

Thanks for this update @cmacknz! As we’re publishing cumulative docs for all 9.x versions, we need to be explicit that this change happens in version 9.3 and we need to keep the previous content for users on versions 9.0-9.2. I’d suggest placing the code blocks in an applies switch:

::::{applies-switch}
:::{applies-item} { serverless: ga, stack: ga 9.3+ }
Code block for versions 9.3+
:::
:::{applies-item} { stack: ga 9.0-9.2 }
Code block for version 9.0-9.2
:::
::::

And for the install-elastic-agents.md, maybe we could rephrase to:

The basic {{agent}} flavor is installed by default using the `elastic-agent install` command with an agent package: `.zip`, .`tar.gz`, `.deb`, `.rpm`, or `.msi`. This flavor includes only the following components:

* Component for implementing all [{{beats}}](beats://reference/index.md)-based integrations:
  * {applies_to}`serverless: ga, stack: ga 9.3+` `elastic-otel-collector`
  * {applies_to}`stack: ga 9.0-9.2` `agentbeat`

[vishaangelova]

One last fix needed:)

[vishaangelova]

With the two suggestions applied, the applies switch will be rendered correctly (tested it locally)—approving to unblock.