`fix_path_env::fix()?` fails when using nushell as default shell

[MylesWritesCode]

Using nushell, I get the following error while using this crate.

  × Missing flag argument.
   ╭─[source:1:1]
 1 │ nu -ilc
   ·    ──┬─
   ·      ╰── flag missing string argument
   ╰────                                     

Running my app by changing the shell environment works as expected (i.e. SHELL=$(which zsh) cargo tauri dev).

I think it might be good to handle the error on line 37 (lib.rs), and use the default shell if that fails. Thoughts?