[EAK-424] components with configured @AllowedChildren annotation allow adding wrong set of components

[liubou-masiuk]

Preconditions: A container component has a parsys\layout container as a part of its markup. The allowed components are configured via @AllowedChildren annotation, no policies are configured for the component.

The user tries to add a disallowed component into the container component by dragging it from the left rail

Expected result: the user is not able to add any components except those that are allowed in the @AllowedChildren annotation
Actual result: the user is able to add components that are allowed for the parent editable (the main page parsys in this example)