Refactor: Determining if a pipeline is run in a fork should come from the backend

Description

Currently, frontend logic is used to determine if a pipeline has the fork tag in the pipeline link:

This logic can be rather brittle: it compares paths (and adds a slash):

 this.pipeline?.project?.full_path !== `/${this.targetProjectFullPath}`

Suggested solution

Have this information calculated in the backend as one of the pipeline properties.