Azure.Sdk.Tools.TestProxy_1.0.0-dev.20220921.3

Fix GZip handling for requests (#4165)

* Fix GZip handling for requests

* Flush GZipStream when compressing.

* Removing flush call - not needed for Test Proxy target platforms

* repair record mode operation. we were exhausting the request body stream.

* Update mock handler

Co-authored-by: scbedd <45376673+scbedd@users.noreply.github.com>