Test recording upgrade concept in Test Proxy

Right now, if either Test Proxy or the SDK adds in new redaction patterns it requires tests for the SDK, or if Test Proxy is adding the redaction all SDKs affected by the new redaction, to re-record test recordings. While in most cases re-recording test recordings is straight forward, it isn't always. and some cases require complex resource deployment which may not be possible by everyone. And, in addition to how easy it is to setup resources, it just costs time to re-record test records, which may not be available quickly.

To ease this, I'm proposing a feature where Test Proxy has the ability to rewrite, or "upgrade", test recordings based on the changes to redactions without requiring a full re-recording to be performed. This should help reduce costs in these scenarios and make the process much quicker. And given new versions of Test Proxy are pushed out centrally, this could be made part of that process, rather than a case where a new version of Test Proxy is released with additional redactions that then breaks CI on affected SDKs without any change on their part.