Self-loop redirects are stored with incorrect metadata

Problem/Motivation

When the audit detects a redirect that points back to itself (a self-loop), the record saved in the database contains incorrect data in the path field. This can cause duplicate records to be created on subsequent audit runs and leads to misleading information in the dashboard when inspecting the details of a self-loop.

Steps to reproduce

1. Create a redirect where the source is an alias of the destination (e.g. source: `about-us`, destination:`internal:/node/1`, where `about-us` is the alias for `node/1`).
2. Run the audit multiple times.
3. Observe that duplicate self-loop records are created, or that the chain detail shows incorrect intermediate redirects.