Unfortunately the C2 admob plugin uses the third party cordova-plugin-ad-admob component, which isn't maintained by us. As far I'm aware the plugin itself has been broken by the maintainer and they haven't looked at it for a long time. So I wouldn't hold up much hope of it being updated to include the user consent dialog.
If your using any third party plugins which involve the collection of user data by you or any party you may need to ask for user consent. You will need to talk to the developer of the plugin to decide what to do in these cases.
If you feel like you need to you can implement your own user consent screens, but I don't feel like I can offer accurate advise on what you must/should/could put onto those screens. You can likely find advise online about it.