[BUG] Upsert action requires existing document in OpenSearch

[graytaylor0]

Describe the bug
The upsert action is supposed to insert a document if it does not exist, and update a document if it does exist. However, the upsert action as part of a bulk request from the opensearch sink receives a document not found error from OpenSearch.

To Reproduce
Steps to reproduce the behavior:

1. Configure and start a pipeline with an opensearch sink with action: upsert
2. Send an Event that does not have an existing document_id for that document in the OpenSearch index
3. Observe the error

WARN  org.opensearch.dataprepper.plugins.sink.opensearch.BulkRetryStrategy - operation 
= Update, error = [2]: document missing

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
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Environment (please complete the following information):

• OS: [e.g. Ubuntu 20.04 LTS]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

[dlvenable]

This is related to #3988.

@graytaylor0 , Is it a duplicate as well?

[graytaylor0]

It is not the same as #3988. #3988 is might be consolidated with #3933 .

However, this one is completely different, and it is strictly focused on upsert not inserting documents when they don't exist