Changed the adding of blocked Variants to a Container to work only if explicitly allowed

Changed the adding of blocked Variants to a Container to work only if explicitly allowed

The behavior, when adding Variants to a PIM Container, in the Item Assignment page was changed.

Usually, all Variants would be added if "Add All Variants" equals true, regardless if the Variant is blocked or not.

With this update, a new field "Allow Blocked Variants" was added, which prevents adding Variants by default.

Therefore to use the old behavior and add all Variants including blocked ones, the field needs to be checked.