[exporter/elasticsearch] Optionally log documents causing indexing failures

[carsonip]

Component(s)

exporter/elasticsearch

Is your feature request related to a problem? Please describe.

Existing config telemetry::log_request_body is not very helpful in debugging because it logs all requests. It will require the user to go through MBs of logs and try to figure out the bad request causing the error.

This is ideally done before #38763 as the bump will strip out even more debugging info by default.

Describe the solution you'd like

Add an opt-in config option to log failed documents

Describe alternatives you've considered

No response

Additional context

No response

[carsonip]

/label -needs-triage

[github-actions]

Pinging code owners:

• exporter/elasticsearch: @JaredTan95 @carsonip @lahsivjar

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