jj git push does not try all ssh keys

[wizardfrag]

Description

I have 2 SSH keys that I use for my git repo, id_ed25519 and id_ed25519_sk (which is a yubikey ssh key with PIN/etc). When I try and run jj git push I get an error and the process exits. I would expect it to try the next key in the list

Steps to Reproduce the Problem

1. Have id_ed25519 and id_ed25519_sk in your ~/.ssh/ folder
2. Run jj git push -c @-

Expected Behavior

1. The private key files are attempted in order until one works or none of them do
   • In my case, the id_ed25519 file is not passworded and requires no additional authentication

Actual Behavior

1. The id_ed25519_sk file is attempted first, which causes the following error:

   Error: failed to authenticate SSH session: Unable to extract public key from private key file: Wrong passphrase or invalid/unrecognized private key file format; class=Ssh (23)
   

I would also be happy if it were possible to configure the SSH key to use, but I can't seem to find that in any documentation/online so am assuming that it's not possible, please feel free to close this issue if it is possible and I've missed something!

Specifications

• Platform: macOS
• Version: 0.23.0

[arxanas]

See also #4979; it's likely that it's a fundamental deficiency for now.