fix(scope): create relationship to a relationship follows old design pattern

[tobybutler405]

Description

Adding a linked entity to a relationship does not seem to follow the new design system.

• create entity button is at the bottom rather than the top
• source entity selection looks wrong no check box or indication of selection

Environment

https://feat-design-system-f.octi.staging.filigran.io/dashboard/observations/indicators/0bef8ad3-bcb0-4ebf-89b2-dcbd4877fc8d/knowledge/relations/8df77f8a-8f8b-4907-977d-37c1b403cf8e

Reproducible steps

open a relationship, click add linked entities

Expected output

Should be more like Indicator based on flow following the new design system

Actual output