Can I delete the tvOS from react native project?

Yes you can delete it but first delete appName-tvOSTests then delete appName-tvOS (otherwise xcode will crash).
After that remove this code from ios/Podfile :

target 'appName-tvOS' do
  # Pods for appName-tvOS

  target 'appName-tvOSTests' do
    inherit! :search_paths
    # Pods for testing
  end

end

Yes, it can be deleted. You wont have any problem submitting it to the app store.