Solved
how to restrict authoring for a specific component added using data-sly-resource
i have added a component inside an other component using data-sly-resource:
<sly data-sly-resource="${breadcrumbPath @ resourceType='my-project/components/content/header/topicmenu', selectors='nav'}"></sly>
i dont want the above component added using data-sly-resource to be authored by the user.
FYI: same component has been added in the main component html twice. one has to be authored (which is working fine as expected), other one should be restricted from authoring.