OG Menu block crashes on Layout Builder defaults when OG context has no group ID

Problem/Motivation

When placing/rendering an ogmenu_block on a Layout Builder page (e.g. /admin/structure/types/manage/{bundle}/display/full/layout), OG context may resolve without a persisted group entity ID. OgMenuBlock::build() still tries to generate entity.ogmenu_instance.create with og_group => '', which triggers:

Symfony\Component\Routing\Exception\InvalidParameterException: Parameter "og_group" for route "entity.ogmenu_instance.create" must match "[^/]++" ("" given)

This causes a 500 AJAX error and can break rendering of the layout page.

Expected behaviour:

• Block should not attempt to build the “Add menu” create link when OG context is missing/unsaved.
• Page should render without fatal errors.

Proposed resolution

In OgMenuBlock::build(), guard create-link route generation behind a check that context is an entity with a non-empty ID.