Acr Tasks fails to download source tarball from Github

[yuehaoliang]

Describe the bug
ACR Tasks should support using a tarball from a remote webserver, but there is an edge case if the remote server is GitHub. The Tasks service interprets the context as a GitHub repository instead of a tarball.

To Reproduce
Steps to reproduce the behavior:

az acr task create -t nvidia/k8s-device-plugin:{{.Run.ID}} -n $MyTask -r $MyRegistry -g $MyResourceGroup -c https://github.com/NVIDIA/k8s-device-plugin/archive/refs/tags/v0.14.3.tar.gz -f deployments/container/Dockerfile.ubuntu --arg GOLANG_VERSION=1.20.5

Expected behavior
Successfully find, download, and extract the tarball.

Additional context
In the backend code, BaseBuildScheduler.BuildSourceLocationUrl() simply checks whether the URL authority contains Github. If it does, it appends .git to the URL, and ACB will handle the URL as a GitSourceControlURL. A potential fix could involve additionally checking whether the URL is a tarball.

[yuehaoliang]

Azure/azure-cli#28190