Enable an arm64 windows CI leg to make sure the SDK continues to build for the supported platform

[ahsonkhan]

See the supported platform matrix:
https://azure.github.io/azure-sdk/cpp_introduction.html#supported-platforms

We have found one linker issue on arm64-windows already, see #1367.
This will help us uncover any other issues that need to be fixed and also stay green going forward.

cc @danieljurek, @vhvb1989

[ahsonkhan]

@antkmsft, can you please manually open a draft PR in vcpkg to confirm our repo is green based on today's commit?