[Key Vault] Redact test values that trigger CredScan warnings

[mccoyp]

Some values in Key Vault test recordings, which aren't sensitive per their test resource status, trigger warnings during credential scans. Here is an example of a warning generated because of a test certificate's value.

These certificate contents have been labeled as permissible since they're not sensitive, but we should still redact these contents from recordings where possible.

[mccoyp]

Moving into a milestone where we re-record with the new test proxy system.

[mccoyp]

Moving to backlog for more investigation at a later time. Redacting certificate values would be straightforward with body key sanitizers that sanitize cer, csr, and value fields in azure-keyvault-certificates recordings (which currently contain test certificate content). Trying this caused failures in playback tests, though:

msrest.exceptions.DeserializationError: Unable to deserialize response data. Data: certificate-content, bytearray, Error: Incorrect padding

Certificate operations need to be able to be decoded from responses into a CertificateOperation object, and this seems to require correct certificate information in recordings. For the time being, I can't think of a straightforward way to sanitize our recordings in a functional way.

[mccoyp]

Closing since this issue hasn't had any progress and isn't pressing.