Add missing dispose for CancellationTokenSource (#13420)

src/Microsoft.PowerShell.Commands.Management/cimSupport/cmdletization/cim/cimChildJobBase.cs

@@ -1087,6 +1087,7 @@ namespace Microsoft.PowerShell.Cmdletization.Cim
                 }
 
                 _cimSensitiveValueConverter.Dispose();
+                _cancellationTokenSource.Dispose();
             }
         }
     }

src/Microsoft.PowerShell.Commands.Management/commands/management/TestConnectionCommand.cs

@@ -838,6 +838,7 @@ namespace Microsoft.PowerShell.Commands
                 if (disposing)
                 {
                     _sender?.Dispose();
+                    _dnsLookupCancel.Dispose();
                 }
 
                 _disposed = true;