Update LifetimeTrackingHttpMessageHandler.Dispose to properly dispose inner handler

Co-authored-by: CarnaViire <3184057+CarnaViire@users.noreply.github.com>

Author: Copilot

src/libraries/Microsoft.Extensions.Http/src/DefaultHttpClientFactory.cs

@@ -361,6 +361,7 @@ public void Dispose()
                 {
                     if (entry != null)
                     {
+                        // During explicit disposal, don't check if can dispose - just force disposal
                         disposables.Add(entry);
                     }
                 }

src/libraries/Microsoft.Extensions.Http/src/ExpiredHandlerTrackingEntry.cs

@@ -35,6 +35,7 @@ public void Dispose()
         {
             try
             {
+                // Always dispose the inner handler when explicitly disposing
                 InnerHandler.Dispose();
             }
             finally

src/libraries/Microsoft.Extensions.Http/src/LifetimeTrackingHttpMessageHandler.cs

@@ -18,6 +18,11 @@ public LifetimeTrackingHttpMessageHandler(HttpMessageHandler innerHandler)
         protected override void Dispose(bool disposing)
         {
             // The lifetime of this is tracked separately by ActiveHandlerTrackingEntry
+            // During explicit disposal, we need to dispose the inner handler
+            if (disposing)
+            {
+                base.Dispose(disposing);
+            }
         }
     }
 }