`nix search` writes excessive diagnostics to stderr

## Describe the bug When run in an Emacs shell buffer, a command like `nix search nixpkgs 'llama\.?cpp'` produces over 117000 lines of output about "evaluating". A very similar problem happens over ssh, for example `ssh localhost nix search nixpkgs 'llama\.?cpp'` sends over 117000 lines to the terminal. In either case, this extra diagnostic output obscures the search results and consumes a lot of bandwidth over a remote connection. ## Steps To Reproduce Debian 13 with `apt-get install -y nix-setup-systemd emacs` and `experimental-features = nix-command flakes` in ~/.nix/nix.conf . 1. Launch Terminal 2. `ssh localhost nix search nixpkgs 'llama\.?cpp'` or 1. Launch Emacs. 2. M-x shell 3. `nix search nixpkgs 'llama\.?cpp'` ## Expected behavior Just the search results unless there is an error. ## Metadata nix-env (Nix) 2.26.3 ## Additional context <!-- Add any other context about the problem here. --> ## Checklist - [x] checked [latest Nix manual] \([source]) - [x] checked [open bug issues and pull requests] for possible duplicates