webhooks: stale hook was not cleaned up

[alejandromumo]

Description
We have identified a potential issue with the management of webhooks for a repository. Upon investigation on Zenodo, we discovered that the repository currently has two active webhooks directed to Zenodo: one created in 2018 and another in 2024.

Problem
Whenever a new release is received, it consistently utilizes the older webhook, which has invalid credentials. Consequently, the releases fail consistently due to this mismatch.

We

Objective
We aim to investigate whether this occurrence is consistent or if it was a one-time incident.

Steps to Reproduce

1. Have a repository jointly owned by two users (user A and user B).
2. Enable the repository with user A on Zenodo.
3. Verify the webhook created on Github.
4. Disable the repository.
5. Enable the repository with user B on Zenodo.
6. Verify the webhook created on Github.

Expected Outcome
If there are indeed two webhooks present in the repository, it indicates an issue with the cleanup process of webhooks.