fix: omz remote execution if ZSH is not present

[SteveLauC]

Standards checklist:

• The PR title is descriptive.
• I have read CONTRIBUTING.md
• The code compiles (cargo build)
• The code passes rustfmt (cargo fmt)
• The code passes clippy (cargo clippy)
• The code passes tests (cargo test)
• Optional: I have tested the code myself

For new steps

• Optional: Topgrade skips this step where needed
• Optional: The --dry-run option works with this step
• Optional: The --yes option works with this step if it is supported by
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If you developed a feature or a bug fix for someone else and you do not have the
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Closes #587

[Un1q32]

Tested on MacOS 14 and Fedora 38, seems to work fine.
Also tested Fedora 38 with omz installed, works as expected.

[chimeworld]

Hi, am I correct in saying this change hasn't been released yet? I am affected by this I think.

❯ topgrade -V
Topgrade 13.0.0

[SteveLauC]

Hi, am I correct in saying this change hasn't been released yet? I am affected by this I think.

❯ topgrade -V

Topgrade 13.0.0

Yes, it is still not released