Storage should return 404 in HTTP status code when object is not found

Storage should respond with status code 404 instead of 400 if object is not found. This was previously proposed in and it's clear that returning 400 is not semantically correct.

Returning 400 with a statusCode embedded in response body also makes it more difficult to differentiate different kind of failures without peaking into response body, which is more expensive for reverse proxies and middleware to implement.