To play with Google Analytics for Web based projects on Firebase we need to use either the Firebase reserved URLs or to copy/update the Firebase config object as the do
In fact the firebase setup:web is not printing the measurementId. But if you refer to Firebase CLI reference you can see that this command is deprecated:
Deprecated. Instead, use apps:sdkconfig and specify web as the platform argument.
You should now use the firebase apps:sdkconfig. From that command you'll have the measurementId.