[ML] Fixing watch creation (elastic#65956)

x-pack/plugins/ml/public/application/jobs/jobs_list/components/create_watch_flyout/create_watch_service.js

@@ -157,6 +157,7 @@ class CreateWatchService {
             id,
             type: 'json',
             isNew: false, // Set to false, as we want to allow watches to be overwritten.
+            isActive: true,
             watch,
           },
         };