Update nixpkgs, add direnv to gitignore (#30292)

This also moves nixpkgs to use `channels.nixos.org` since those tarballs
are 30mb in size as compared to 45mb github ones

Release Notes:

- N/A 

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cc @P1n3appl3
f01af006e1Stanislav Alekseev committed on 5/13/2025, 8:45:22 AM· committed by GitHubparent01488c4
3 files changedLine totals unavailable