Remove some unhandled rejections in tests

Summary: Fixed several tests that caused uncaught promise rejects to fire after the tests finished. This caused jest to fail if there are too many of them.

Reviewed By: aigoncharov

Differential Revision: D32118124

fbshipit-source-id: 50734dab6dee2efec7f056940af72858b27b1707

desktop/flipper-plugin/src/test-utils/test-utils.tsx

@@ -334,8 +334,10 @@ export function startDevicePlugin<Module extends FlipperDevicePluginModule>(
     },
   };
   (res as any)._backingInstance = pluginInstance;
-  // we start connected
-  pluginInstance.activate();
+  if (!options?.startUnactivated) {
+    // we start connected
+    pluginInstance.activate();
+  }
   return res;
 }