[Cloud Shell] Pre-Deployment Testing Environment

[necusjz]

We need a Cloud Shell testing environment so we can assess the overall quality before each build is deployed to Cloud Shell, instead of discovering issues afterward and having to ship hotfixes.

[yonzhan]

Pre-Deployment Testing Environment for Cloud Shell

[microsoft-github-policy-service]

🔔 Routing this issue to @Azure/act-quality-productivity-squad.