docs: updated contrib guide

Author: JairajJangle

CONTRIBUTING.md

@@ -66,14 +66,6 @@ To run the example app on iOS:
 yarn example ios
 ```
 
-To confirm that the app is running with the new architecture, you can check the Metro logs for a message like this:
-
-```sh
-Running "ReactNativeCheckboxExample" with {"fabric":true,"initialProps":{"concurrentRoot":true},"rootTag":1}
-```
-
-Note the `"fabric":true` and `"concurrentRoot":true` properties.
-
 To run the example app on Web:
 
 ```sh