add openmct error notif

Author: jvigliotta

src/persistence/MCWSPersistenceProvider.js

@@ -31,6 +31,10 @@ export default class MCWSPersistenceProvider extends BaseMCWSPersistenceProvider
 
       // it's a network error, we don't want to create a new object
       if (error.status !== 404) {
+        this.openmct.notify.error(
+          `Error: ${error.message ?? 'Unknown error'}. Check network connection and try again.`
+        );
+
         return {
           identifier,
           type: 'unknown',