+++ This bug was initially created as a clone of Bug #1129937 +++

During testing of jsc#SLE-2995 and playing editing form.yml to create different visualizations, it was found that:

- `$scope: readonly` combined with $default allows to edit a field.

It is easy to check using a small portion of this example:
https://github.com/yast/yast-configuration-management/blob/master/test/fixtures/formulas-ng/test-formula/form.yml

Expectation:
According to documentation in: https://www.suse.com/documentation/suse-manager-3/3.2/susemanager-best-practices/html/book.suma.best.practices/best.practice.salt.formulas.and.forms.html#best.practice.salt.formulas.pillar

The $scope: readonly option makes a field read-only.
It can be used to show a user data which should be known, but should not be editable.
This option only makes sense in combination with the $default attribute.