I think this should fix the CI issues with Eval jobs:

1. Duplicated workflows because `synchronize` / `opened` were triggering
distinct runs. This caused failed job entries because the duplicated
workflows had a shared concurrency group and so one would pre-empt the
other.

3. Removes the no-op job, introduced as an attempted workaround in
   https://github.com/zed-industries/zed/pull/29420.

These should correctly show as "Skipped" now:

| Before | After |
| - | - |
| <img width="359" alt="Screenshot 2025-06-26 at 9 57 04"
src="https://github.com/user-attachments/assets/6ddd4f46-27c7-4d82-98ba-0f1166fc55e7"
/> | <img width="355" alt="Screenshot 2025-06-26 at 10 09 54"
src="https://github.com/user-attachments/assets/5faade2c-f17c-447a-9af9-6396f9e53016"
/> |

Release Notes:

- N/A