[FR] Change GenerateXmlFromGoogleServicesJson.spamguard to public, or otherwise allow setting this to true

### Feature proposal

GenerateXmlFromGoogleServicesJson has a field "spamguard" that suppresses the bundle id popup from showing. It would be great if it was public so that end users could turn off this popup easily, without having to use reflection to force it off. We have a build script that configures our google services file, and we don't need to ever see this popup during regular development in the editor.