allow service_metadata to be optional in case there are no services in an app (#3672)

Co-authored-by: David Townley <davidtownley@Davids-MacBook-Air.local>

dashboard/src/main/home/app-dashboard/app-view/tabs/activity-feed/events/types.ts

@@ -19,7 +19,7 @@ const porterAppDeployEventMetadataValidator = z.object({
     service_deployment_metadata: z.record(z.object({
         status: z.string(),
         type: z.string(),
-    })),
+    })).optional(),
 });
 const porterAppBuildEventMetadataValidator = z.object({
     repo: z.string().optional(),