Reconsider necessity of having public origin redirects in POST apis

Some http clients, such as [https://api.flutter.dev/flutter/dart-io/HttpClientRequest/followRedirects.html]()
Will not follow redirects on POST requests.
Therefore returning 308 in POST apis may cause problems. If it is not necessary, lets remove it.

Trace the public-origin redirect handling used by POST APIs and inspect how 308 responses are covered. Verify whether those redirects are required for the API flow; done means reaching an evidence-backed decision and updating the affected behavior and tests if removal is approved.

Written by the indexing model from the issue text.