[exporter/elasticsearchexporter] Fix bulk indexer to capture indexing errors for collector events metrics

[lalith47]

Description:
Return Elasticsearch bulk indexer errors if any so OTEL Collector would count them properly in its internal metrics.
For address this, added error channel in bulk indexer so that it can send error to the channel.

Link to tracking Issue: #32302
Testing:
In Progress

This approach has some issues. When failed events are received otelcol_exporter_sent_log_records otelcol_exporter_send_failed_log_records both are incrementing incorrectly.

From debugging, found that documents are periodically flushed for a given flushInterval. Before the flush triggers, if we add some documents they are marked as sucess. Need an alternate approach or suggestions for fixing error metrics

Documentation: No added documentation

[linux-foundation-easycla]

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• ✅ login: lalith47 / name: Lalith Niddapu (73c93dc)

[carsonip]

If I understand correctly, this is the same issue described in #32377, and #32632 is an attempt to resolve it.

[lalith47]

Hey @carsonip, Thanks for letting me know. I was also doing similar analysis.
We can close this PR as #32632 solves the actual problem.