Remove firewall setting from copilot-setup-steps.yml

This doesn't actually work as an env var, it needs to be set as a GitHub Actions variable in the repository settings.

Author: akoeplinger

.github/workflows/copilot-setup-steps.yml

@@ -12,10 +12,6 @@ on:
 permissions:
   contents: read
 
-env:
-  # Allow Copilot to access Visual Studio assets URLs needed for NuGet restore
-  COPILOT_AGENT_FIREWALL_ALLOW_LIST_ADDITIONS: "vsblob.vsassets.io"
-
 jobs:
 
   copilot-setup-steps:
@@ -31,4 +27,4 @@ jobs:
 
       - name: Check dotnet version
         run: |
-          dotnet --version
+          dotnet --version