fix(auth): `ForgotPasswordScreen` display email within input box

Description

If we set the email property like below:

SignInScreen(
            email: 'some@email.com',
            actions: [
              ForgotPasswordAction((context, email) {
                Navigator.pushNamed(
                  context,
                  '/forgot-password',
                  arguments: {'email': email},
                );
              }),
// Rest of setup

We should see it in the ForgotPasswordScreen. Now, it displays correctly:

If we don't, it will still work as previously taking the value from the email input from sign-in screen.

Related Issues

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Breaking Change

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[ ] Yes, this is a breaking change.
[X] No, this is not a breaking change.

firebase / FirebaseUI-Flutter