synthetics - unskip flaky test (#142801) (#142866)

(cherry picked from commit 8efefb1)

Co-authored-by: Dominique Clarke <[email protected]>

x-pack/test/api_integration/apis/uptime/rest/add_monitor_project.ts

@@ -707,13 +707,15 @@ export default function ({ getService }: FtrProviderContext) {
             ...projectMonitors,
             keep_stale: false,
             monitors: testMonitors,
+            project: 'test-project-2',
           });
 
         const messages = await parseStreamApiResponse(
           projectMonitorEndpoint,
           JSON.stringify({
             ...projectMonitors,
             keep_stale: false,
+            project: 'test-project-2',
           })
         );