Ref: https://github.com/opf/openproject/pull/21932

### Steps to reproduce

Reproduces with the GitLab integration (the GitHub integration shows the same class of mislinking):

1. Begin of the insertion End of the insertion Connect **two** GitLab repositories Begin of the insertion(_Repo A_End of the insertion Begin of the deletion (*Repo A*End of the deletion and Begin of the insertion_Repo B_)End of the insertion Begin of the deletion *Repo B*)End of the deletion to the same OpenProject instance. Begin of the insertion

End of the insertion Begin of the deletion
End of the deletion 2. Begin of the insertion End of the insertion In Begin of the insertion_Repo A_,End of the insertion Begin of the deletion *Repo A*,End of the deletion open merge request `!5` referencing a work package, e.g. `OP#100`. Begin of the insertion

End of the insertion Begin of the deletion
End of the deletion 3. Begin of the insertion End of the insertion In Begin of the insertion_Repo B_,End of the insertion Begin of the deletion *Repo B*,End of the deletion open merge request `!5` (GitLab numbers merge requests per project, so this is also `!5`) referencing a different work package, e.g. `OP#200`. Begin of the insertion

End of the insertion Begin of the deletion
End of the deletion 4. Begin of the insertion End of the insertion Let both `merge_request` webhooks reach OpenProject. Begin of the insertion


**Example with two repositories connected:**

| MR | Specified reference | Linked to |
| ------------------------------ | ------------------- | ------------------ |
| `first_repo/merge_requests/1` | `OP#101` | `WP#101` ✅ |
| `first_repo/merge_requests/2` | `OP#102` | `WP#102` ✅ |
| `second_repo/merge_requests/1` | `OP#201` | `WP#101` ❌ (wrong!) |
| `second_repo/merge_requests/2` | `OP#202` | `WP#102` ❌ (wrong!) |

End of the insertion Begin of the deletion

End of the deletion ### What is the buggy behavior?

A webhook for Begin of the insertion_Repo B_'sEnd of the insertion Begin of the deletion *Repo B*'sEnd of the deletion `!5` matches and overwrites the record created for Begin of the insertion_Repo A_'sEnd of the insertion Begin of the deletion *Repo A*'sEnd of the deletion `!5`, because the lookup matches on the per-project merge request number Begin of the insertion(GitLab'sEnd of the insertion Begin of the deletion (GitLab'sEnd of the deletion internal ID, `iid`), which is `5` in both repositories. Work packages then link to a merge request from the wrong repository — e.g. `#100` shows Begin of the insertion_Repo B_'sEnd of the insertion Begin of the deletion *Repo B*'sEnd of the deletion merge request — and the link flips back and forth as each Begin of the insertionrepository'sEnd of the insertion Begin of the deletion repository'sEnd of the deletion webhooks arrive. The same affects issues, pipelines and comments. There is no error; the linking is silently wrong.

### What is the expected behavior?

Each merge request, pull request and issue is identified by its unique webhook URL rather than a number that repeats across repositories. Begin of the insertion_Repo A_'sEnd of the insertion Begin of the deletion *Repo A*'sEnd of the deletion `!5` links only to `#100`, Begin of the insertion_Repo B_'sEnd of the insertion Begin of the deletion *Repo B*'sEnd of the deletion `!5` links only to `#200`, and pipelines/comments attach to the correct Begin of the insertionrepository'sEnd of the insertion Begin of the deletion repository'sEnd of the deletion record.

### Environment

Server-side bug in the GitHub/GitLab integration modules — independent of installation type, browser, OS and language. Present in all current versions whenever more than one repository is connected; reproduced on the latest `dev`. Begin of the deletion
End of the deletion