Fetch with `ssh` works, but pull does not.

**Describe the bug**

Fetch works... pull doesn't.

**To Reproduce**
Steps to reproduce the behavior:
1. `shift+f` -> fetch remote, yubikey touch for SSH, works fine :ok_hand:
2. `p` -> pull remote, yubikey touch for SSH, `fetch failed: git error: Bad credentials.` :sob:

**Context (please complete the following information):**
- OS/Distro + Version: Pop!_OS
- GitUI Version: #2157 branch
- Rust version: 1.77.0

**Additional context**

I have multiple ssh and gpg configs that occasionally will error on one that is incorrect, but then try another that is for `git` - I have not tried to see if that is the issue here, but I do not think it's at play in testing so far.

Comienza reproduciendo la diferencia entre la ruta de fetch `shift+f` y la ruta de pull `p` con autenticación SSH y YubiKey en el entorno indicado. Compara el comportamiento de autenticación de ambas operaciones y verifica el fix confirmando que pull se completa sin `Bad credentials`.

Escrito por el modelo de indexación a partir del texto del issue.