Cascade remove in report knowledge graph is not working as expected

[JeremyCloarec]

Description

When removing a relation from a report graph, when choosing a cascade remove, the relation is deleted even if it is contained in an other container.

Reproducible Steps

1. Create a new grouping
2. Go to the knowledge graph, add two entities and create a relationship between them
3. Create a new report
4. Go to the knowledge graph, add the two same entities and add the same relationship between them
5. Remove this relationship choosing a cascade remove

Expected Output

The relationship still being there in the grouping

Actual Output

The relationship is entirely deleted