iOS Extensions Support

I'm trying to add Firebase to an iMessage app extension.
I created a project in Firebase and added two iOS apps, one for the main app (id: `com.company.app`), and the other for the extension (id: `com.company.app.stickers`).
I followed the guides and added the proper `GoogleService-Info.plist` file to each target.
But when I run the extension I see error this in Xcode output:

> 6.9.0 - [Firebase/Core][I-COR000008] The project's Bundle ID is inconsistent with either the Bundle ID in 'GoogleService-Info.plist', or the Bundle ID in the options if you are using a customized options. To ensure that everything can be configured correctly, you may need to make the Bundle IDs consistent. To continue with this plist file, you may change your app's bundle identifier to 'com.company.app.stickers'. Or you can download a new configuration file that matches your bundle identifier from https://console.firebase.google.com/ and replace the current one.

I made sure the bundle identifier of the extension is actually `com.company.app.stickers`. But the interesting thing is that when I tried to use the main `GoogleService-Info.plist` for the extension target the error disappeared although the bundle id in this plist file is `com.company.app` and the bundle id of the extension target is different!

So, am I doing anything wrong here? Or iOS extensions are not supported?