Unable to assign values to Additional Fields

[MarkAStepp]

Describe the bug
The additionalSignupFields seem to be assigned before the user is logged in. I tried to assign the defaultValue from information after a google authentication but nothing happens because the default values are still blank when it is assigned.

I can get to the additionalSignupData prior to it showing the additional fields card but I can't seem to be able to assign the values of the fields. it is showing that the additionalSignupData is null at the point it gets to onSwitchToAdditionalFields.

  onSwitchToAdditionalFields: (signupData) {
    signupData.additionalSignupData?.addAll({
      'first_name': google_given_name,
      'last_name': google_family_name,
    });
    return Future.value(null);
  },

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
Be able to assign the additionalSignupData prior to showing the additional data card

Screenshots
If applicable, add screenshots to help explain your problem.

Information (please complete the following information):

• Device: MacBookPro
• Platform Web
• Flutter version: Flutter (Channel stable, 3.24.2, on macOS 14.6.1 23G93 darwin-x64, locale en-US)
• Package version flutter_login: ^5.0.0

Additional context
Sample code to make this happen would be helpful if I'm simply doing it incorrectly.