FlutterAppRequiredException: The current directory does not appear to be a Flutter application project

You need to first redirect to your application path in CLI

cd app_name

Try again flutterfire configure command after that.

You must make sure that in your pubspec.yaml the following lines are on the start of dependencies place, ex:

dependencies:
  flutter:
    sdk: flutter

Make sure your pubspec.yaml file is well defined and correct. In my case, I had erased after dependencies

  flutter:
    sdk: flutter
  ...

The correct format may be in flutter 3.3.0 Flutter and the pubspec file

name: myapp
version: 1.0.0+1
publish_to: none
description: A new Flutter project.
environment: 
  sdk: '>=2.18.0 <3.0.0'

dependencies: 
  cupertino_icons: 
 
  flutter:
    sdk: flutter

dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:
  assets:
    - assets/
 
  uses-material-design: true