[TA] Undo passing endpoint and api key as static in our pipelines

[mssfang]

This was done while we target a static PPE endpoint.
Once it is available for us to consume, we should remove this static references. Which we don't create the resource for testing pipeline.

Before Preview 5, we used AAD as the authentication for testings. But preview 5 we are restricted to use the static PPE endpiont because the service team has not fully roll the new service version out. After preview 5 or the service GAed, we have will readopt the "create resource when needed".