FirebaseCrashlytics plugin not been recognized by cordova

i am trying to use firebase crashlytics in ionic 4, but when i build my app this message is shown in the developer console in chrome, and firebase crashlytics is not working, I have already configurated the build.gradle and imported the google-service.json file.


The app builds successfully but firebase crashlytics plugin is not recognized by cordova

the console shows :

Install the FirebaseCrashlytics plugin: ‘ionic cordova plugin add cordova-plugin-firebase-crashlytics’