[GRPC] Update gRPC usage instructions and fix java examples

[karenyrx]

Description

1. Update the Java examples to have error handling scenarios
2. Update the gRPC usage guide to put more important sections first for clarity

Issues Resolved

Closes #10999

Version

3.3+

Frontend features

If you're submitting documentation for an OpenSearch Dashboards feature, add a video that shows how a user will interact with the UI step by step. A voiceover is optional.

Checklist

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[github-actions]

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[finnegancarroll]

https://github.com/opensearch-project/opensearch-protobufs/compare/2ea2050d375d71ff142279c3cdccf0b4c692c678..b6f889416da83b7dc4a0408347965e7820bd61d0

I think there were a couple minor name changes in bulk request:
setIndex -> setXIndex
setId -> setXId

OperationContainer added to BulkBody:

        BulkRequestBody deleteBody = BulkRequestBody.newBuilder()
                .set(deleteOp)

->

        BulkRequestBody deleteBody = BulkRequestBody.newBuilder()
                .setOperationContainer(OperationContainer.newBuilder().setDelete(deleteOp).build())

[finnegancarroll]

System.out.println("Total hits: " + hits.getTotal().getTotalHits().getValue());

[finnegancarroll]

Added couple comments on variable name changes - otherwise LGTM.

[karenyrx]

hi @kolchfa-aws could you help review this? Tech review is complete. Thanks!

[kolchfa-aws]

Thank you, @karenyrx! Please see my comments and let me know if you have any questions.

[natebower]

Doc and editorial reviews complete. LGTM