[BUG] salt-ssh 3007.0 attempts to run commands in default shell, even if default shell is fish

Description

salt-ssh attempts to run commands in the default shell, even if the default shell is fish. For example, { ... } from here is valid in bash, but this causes an error in fish:

fish: Unknown command: '{ brew --prefix }'
fish: '{ ... }' is not supported for grouping commands. Please use 'begin; ...; end'

Setup

• onedir packaging 3007.0
• macOS Sonoma 14.4

Steps to Reproduce the behavior

brew install fish
chsh -s /opt/homebrew/bin/fish

Close and re-open Terminal.app

Run any salt-ssh command

Expected behavior

No hang or error.

Versions Report

Cannot run salt --versions-report as it hangs instead.

Additional context

My present workaround is:

chsh -s /bin/bash

And set Terminal > Settings... > Shells open with: to Command (complete path): with /opt/homebrew/bin/fish

This leaves $SHELL set to /bin/bash.

Note that the comment here is both out-of-date and incorrect (su doesn't run sh – it runs the user's login shell, which can be any valid shell)

https://github.com/saltstack/salt/blob/d036b1177efeec175164571e9cc07b52cddf7844/salt/modules/cmdmod.py#L472-L475

The previous line of code it refers to was:

https://github.com/saltstack/salt/commit/ab8b39ce1043c2421e5c750d90bd529be5e32250#diff-700b7d75700c9eafa3ee48d01236e59f37b2ed81d998267136fbcc0224766497R419-R421