[BUG]: Fix document upsert returning 404:0s.

[jeet1995]

We are continuously addressing and improving the SDK, if possible, make sure the problem persist in the latest SDK version.

Describe the bug
In certain scenarios, a document upsert could return a 404:0 which doesn't abide by upsert semantics which is to create if a document doesn't exist or update otherwise - so a 404:0 is actually invalid.

To Reproduce
Reproduces in certain bulk upsert scenarios from the SDK's perspective.

Expected behavior
A document upsert shouldn't return a 404:0.