C#: Change the All NuGet feed reachable telemetry.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetPackageRestorer.cs

@@ -820,9 +820,9 @@ private bool CheckSpecifiedFeeds(HashSet<string> feeds, out HashSet<string> reac
 
             reachableFeeds = GetReachableNuGetFeeds(feedsToCheck, isFallback: false, out var isTimeout).ToHashSet();
 
-            var noTimeout = !isTimeout;
-            EmitUnreachableFeedsDiagnostics(noTimeout);
-            return noTimeout;
+            var allReachable = reachableFeeds.Count == feedsToCheck.Count;
+            EmitUnreachableFeedsDiagnostics(allReachable);
+            return !isTimeout;
         }
 
         /// <summary>