KeyVault: Fix test failures

[antkmsft]

The reason for this, I think, is that after the change that enabled running live tests against WinHTTP transport, and a few subsequent fixes to record and playback (updated regex for secrets, removed cookie from recordings), KeyVault pipeline started to fail, and we need to update the recordings (Storage did that - https://github.com/Azure/azure-sdk-for-cpp/pull/5070/files#diff-8197b617f0faa3471ca4ae5d7bc8ed10aaf1c67656cdd7071570cd08994d3a88R5).
Possibility number 2 - we need to update WinHTTP transport to closer align with the libcurl transport (see https://github.com/Azure/azure-sdk-for-cpp/pull/5071/files#r1373997631).

Either way, please make the /azp run cpp - keyvault - ci and /azp run cpp - keyvault green.

[LarryOsterman]

If there is ever a question about whether the winhttp or curl behavior is correct, the winhttp behavior should be assumed to be correct. Curl is a HTTP client written by the Azure SDK for C++ team. WinHTTP is an HTTP client written by the Windows HTTP client transport team (who also writes the .Net HTTP client).

So IMHO possiblity #2 should be worded as "we need to update the libcurl transport to closer align with the winhttp transport".

Edit to add: We could contemplate using libCURL in non-connection-only mode, which should work for every client SDK except for storage (the default libcurl behavior requires that the request and response payload be provided to the curl_easy APIs).