feat: add support to extended checkbox field in account settings

[BryanttV]

Description

This PR adds support to Extended CheckBox Fields in the Account Settings.

Supporting information

• https://github.com/fccn/nau-technical/issues/279
• https://github.com/eduNEXT/consulting-issues-mapping/issues/10

Testing instructions

1. Create a Tutor environment in the Redwood version.
2. Install nau-openedx-extensions plugin with the changes in this PR.
3. Create a mount of edx-platform with the changes in this PR.
4. Update the account.redirect_to_microfrontend Waffle Flag. Set Everyone to No. This allows access to the legacy interface.
5. Go to {lms_domain}/account/settings
6. You should see the new checkbox field in the Additional Information section.
7. Try to update the field and verify that the value was updated in the model.

Screenshots

[MaferMazu]

Thanks for this PR, @BryanttV. The function works as expected.

My suggestion here is to improve the indentation in lms/static/js/student_account/views/account_settings_fields.js to make it easier to read and clear that the following functions are attached to the ExendedFieldCheckboxFieldView.

[MaferMazu]

Thanks @BryanttV. This looks good to me.

[igobranco]

LGTM ✔️