Meilisearch index documents were not synced properly when any block with children blocks like units, subsections, sections etc. were being deleted as the `XBLOCK_DELETED` is only triggered for the deleted block.
This PR fixes it by deleting all index documents that contain the deleted block in its `breadcrumbs` field as only blocks that are children of this block will have it its breadcrumbs field.
Similarly, the entity links that store links between course and library blocks was not synced properly due to children `ContainerLinks` not being deleted.