Revert "Allow always_allow patterns for Nushell, Elvish, and Rc shells" (#48050)

Reverts zed-industries/zed#47908

This PR inadvertently caused a regression:

- https://github.com/zed-industries/zed/issues/48047
72b151e3aaJoseph T. Lyons committed on 1/30/2026, 9:26:13 PM· committed by GitHubparentcfd6144
28 files changedLine totals unavailable