Refresh agent dashboard panel after create\update\delete operations (#1861)

* Edit alert WIP

* A couple alert edit bugs

* Hook up dashboard refresh notification

* Hook onchange event to other agent service calls

* Switch update handler to scalar value

* Add null check on handler callback

src/sql/workbench/api/node/sqlExtHost.api.impl.ts

@@ -265,6 +265,10 @@ export function createApiFactory(
 			};
 
 			let registerAgentServicesProvider = (provider: sqlops.AgentServicesProvider): vscode.Disposable => {
+				provider.registerOnUpdated(() => {
+					extHostDataProvider.$onJobDataUpdated(provider.handle);
+				});
+
 				return extHostDataProvider.$registerAgentServiceProvider(provider);
 			};