Add windows arm64 to set of standalone builds for the test-proxy (#12550)

* Apply suggestion from @mikeharder

Co-authored-by: Mike Harder <[email protected]>

Author: scbedd

tools/test-proxy/ci.yml

@@ -38,12 +38,16 @@ extends:
     - rid: win-x64
       framework: net8.0
       assembly: Azure.Sdk.Tools.TestProxy
+    - rid: win-arm64
+      framework: net8.0
+      assembly: Azure.Sdk.Tools.TestProxy
     - rid: linux-x64
       framework: net8.0
       assembly: Azure.Sdk.Tools.TestProxy
     - rid: linux-arm64
       framework: net8.0
       assembly: Azure.Sdk.Tools.TestProxy
+
     TestPreSteps:
       - pwsh: |
           #vso[task.setvariable variable=COMPlus_Pkcs12UnspecifiedPasswordIterationLimit]-1