ManualProcess: Update input-elastic_agent to v6.2.4 for main

[karenzone]

Update input-elastic_agent with latest content (v6.2.2) from input-beats

Input-elastic_agent is an alias of input-beats. Updating docs for elastic_agent is a manual process, consisting of copying content from the generated input-beats output to the input-elastic_agent output in logstash-docs.

IMPORTANT

Copy only from the :version: section (Line 11) to the bottom of the file. The custom variables for input-elastic_agent are different from input-beats, and must be preserved.

NOTE: The only docs change this time was the version bump/date. Rather than copying over the whole file, I just updated that info.

[karenzone]

@elasticmachine run elasticsearch-ci/docs

[karenzone]

Builds cleanly and renders as expected