fix: suppress NU1900 from private NuGet feed in CI restore

NuGet vulnerability audit queries all sources in nuget.config even when AccessToNugetFeed=false (which only affects RestoreSources via MSBuild). The private Azure DevOps feed is unreachable in CI without auth, causing NU1900 treated as warning-as-error.

Add --ignore-failed-sources to dotnet restore so the unavailable private source is skipped gracefully.

Author: BenjaminMichaelis

.github/workflows/PR-Build-And-Test.yml

@@ -29,7 +29,7 @@ jobs:
             ${{ runner.os }}-nuget-
 
       - name: Restore with dotnet
-        run: dotnet restore /p:AccessToNugetFeed=false
+        run: dotnet restore /p:AccessToNugetFeed=false --ignore-failed-sources
 
       - name: Restore local dotnet tools
         run: dotnet tool restore