As an admin, I want to ensure that content type attribute migrations handle non-existent values gracefully, so that the system remains stable and no runtime errors occur.

Steps to Reproduce:

1. In the admin panel, navigate to the content type management section.
2. Add a "Select" attribute to the "Landing Page" content type with the following options:
   • Option 1
   • Option 2
   • Option 3
3. Create a new Landing Page and select "Option 2" for the "Select" attribute.
4. Create and run a migration with the following settings:

yaml

fieldSettings:
    isMultiple: false
    options:
        0: Option 1
        2: Option 3 

1. Open the previously created Landing Page in the admin panel.

Actual Result:

• A runtime error occurs stating "Key x for array with keys doesn't exist".

Expected Result:

• The content type attribute should switch to a default value, and no exception should be thrown.

Issues to Address:

1. Migrations Execution:
   • Ensure it is possible to update the value of objects using the value that is to be removed to another value.
2. Options Structure:
   • Use value-label pairs instead of index-label pairs, to facilitate easy reordering of options.
3. Admin Stability:
   • Prevent admin panel crashes when a non-existent value is selected.

Acceptance Criteria:

1. Migrations can update object values to another valid value before removing an existing option.
2. Content type attribute options are defined using value-label pairs.
3. The system automatically switches to a default value if a non-existent value is selected.
4. No runtime errors occur when navigating the admin panel with a non-existent content type attribute value.