[release/5.0] Add Support to ActivitySource events in DiagnosticSourceEventSource (#41681)

Co-authored-by: Tarek Mahmoud Sayed <tarekms@microsoft.com>

Author: github-actions[bot]

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/ActivitySource.cs

@@ -44,6 +44,8 @@ public ActivitySource(string name, string? version = "")
                     }
                 }, this);
             }
+
+            GC.KeepAlive(DiagnosticSourceEventSource.Logger);
         }
 
         /// <summary>