chore(api): clarify documented API error responses (#3965)

## Summary

Clarifies documented error responses for Python users without changing
existing client behavior.

## Changes

- Document applicable errors across organization, inference, media and
resource APIs.
- Preserve existing public methods, exception types and runtime
behavior.

Co-authored-by: markstuart-oai <323302876+markstuart-oai@users.noreply.github.com>