NoSuchMethodError: tried to call a non-function, such as null: 'dart.global.firebase.auth' when creating new user

I have been trying to get firebase authentication to work on my flutter web app however when I try to make a new user I end up with the following problem.

When running the line:

UserCredential result = await _auth.signInAnonymously();

I receive the following error:

NoSuchMethodError: tried to call a non-function, such as null: 'dart.global.firebase.auth'

I have tried following the fixes of others with the same issue such as moving things into the head of my index.html file, however nothing has worked so far.

here is my pubspec.yaml

description: A new Flutter project.

# The following line prevents the package from being accidentally published to
# pub.dev using `pub publish`. This is preferred for private packages.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1

environment:
  sdk: ">=2.7.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  cupertino_icons: ^1.0.2
  firebase: ^9.0.1
  firebase_storage: ^8.0.4
  
  firebase_auth: ^1.1.4
  flutter_login: ^1.0.10
  flutter_svg: ^0.19.3
  google_sign_in: ^5.0.2

dev_dependencies:
  flutter_test:
    sdk: flutter

# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec
# The following section is specific to Flutter.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  assets:
    - assets/logo.gif
  #   - images/a_dot_ham.jpeg
  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.dev/assets-and-images/#resolution-aware.
  # For details regarding adding assets from package dependencies, see
  # https://flutter.dev/assets-and-images/#from-packages
  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.dev/custom-fonts/#from-packages

and here is my index.html

<html>
<head>
  <!--
    If you are serving your web app in a path other than the root, change the
    href value below to reflect the base path you are serving from.

    The path provided below has to start and end with a slash "/" in order for
    it to work correctly.

    Fore more details:
    * https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base
  -->
  <base href="/">

  <meta charset="UTF-8">
  <meta content="IE=Edge" http-equiv="X-UA-Compatible">
  <meta name="description" content="A new Flutter project.">

  <!-- iOS meta tags & icons -->
  <meta name="apple-mobile-web-app-capable" content="yes">
  <meta name="apple-mobile-web-app-status-bar-style" content="black">
  <meta name="apple-mobile-web-app-title" content="flutter_4paul">
  <link rel="apple-touch-icon" href="icons/Icon-192.png">

  <!-- Favicon -->
  <link rel="icon" type="image/png" href="favicon.png"/>

  <title>flutter_4paul</title>
  <link rel="manifest" href="manifest.json">


 
    <!-- This script installs service_worker.js to provide PWA functionality to
         application. For more information, see:
         https://developers.google.com/web/fundamentals/primers/service-workers -->

  <script src="https://www.gstatic.com/firebasejs/8.5.0/firebase-app.js"></script>
  
  <!-- TODO: Add SDKs for Firebase products that you want to use
       https://firebase.google.com/docs/web/setup#available-libraries -->
  
  <script src="/__/firebase/8.5.0/firebase-auth.js"></script>
  <script src="/__/firebase/8.5.0/firebase-database.js"></script>
  
  <script>
    // Your web app's Firebase configuration
    // For Firebase JS SDK v7.20.0 and later, measurementId is optional
    var firebaseConfig = {
      //my config info
    };
    // Initialize Firebase
    firebase.initializeApp(firebaseConfig);
    
  </script>
  </body>
  <script>
    if ('serviceWorker' in navigator) {
      window.addEventListener('flutter-first-frame', function () {
        navigator.serviceWorker.register('flutter_service_worker.js');
      });
    }
  </script>
  <script src="main.dart.js" type="application/javascript"></script>
</head>


<!-- The core Firebase JS SDK is always required and must be listed first -->
</html>