Fix nix develop

[supersven]

For unknown reasons, nix develop <repo>/\# does not work with buildEnv. mkShell works fine, though.

Before the fix (on my machine):

➜  src nix develop wire-server/\# --command which yq
which: no yq in (/nix/store/28wd9y9ndcgjqc7qrjszvghfv4r2kdrn-patchelf-0.15.2/bin:/nix/store/48nhpn1dv5pn74018agdz7qrbiik2sd5-coreutils-9.8/bin:/nix/store/xw0fhda3s7skl5b3pniian88dw4v5wzh-findutils-4.10.0/bin:/nix/store/ljk8wffznak0q9srdgv0s9gj92bihx60-diffutils-3.12/bin:/nix/store/dvy1v72pqn0796fxsh20s13hmj5pr7y1-gnused-4.9/bin:/nix/store/bf550igzh3h95x25yg0ibjr3s8hwjzv0-gnugrep-3.12/bin:/nix/store/z8g912b1xmi9g7jzwyjbchkbwa081ykq-gawk-5.3.2/bin:/nix/store/hy7mnzbwngafq13i5gqzq3ffjwmrpi3d-gnutar-1.35/bin:/nix/store/4r29xglhvghzzqswwkll8b2q293yqlqm-gzip-1.14/bin:/nix/store/3cgh22sipndi73jgmjxdwz00d9djplfd-bzip2-1.0.8-bin/bin:/nix/store/xp29m40k5crmry03k3z2la03l06y3r2i-gnumake-4.4.1/bin:/nix/store/fwr62xmh06l8y8zfgc5m18pfap9b8az0-bash-5.3p3/bin:/nix/store/m28pw7a348j1rspzwxqf59cvdw5q8lsp-patch-2.8/bin:/nix/store/b991fj4kanf5anzvhzp2lgxbdp05amnc-xz-5.8.1-bin/bin:/nix/store/nbyy447nn6grvdindk8as26z9fwypc79-file-5.45/bin:/run/wrappers/bin:/home/sven/.nix-profile/bin:/nix/profile/bin:/home/sven/.local/state/nix/profile/bin:/etc/profiles/per-user/sven/bin:/nix/var/nix/profiles/default/bin:/run/current-system/sw/bin)

After:

➜  src nix develop wire-server/\# --command which yq
warning: Git tree '/home/sven/src/wire-server' is dirty
warning: Git tree '/home/sven/src/wire-server' is dirty
/nix/store/vclh54r4a66ipnqhclrf8xa8h705hyw4-python3.13-yq-3.4.3/bin/yq

Ticket: https://wearezeta.atlassian.net/browse/WPB-20616

Checklist

• Add a new entry in an appropriate subdirectory of changelog.d
• Read and follow the PR guidelines