Remove 'vercel' from nix packages list

[ethernet8023]

we ripped vercel out earlier, but missed this one :)

What does this PR do?

nix setup was trying to install the removed vercel extra from pyproject.toml. this removes it.

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• removed "vercel" from nix/packages.nix

[github-actions]

🔎 Lint report: ethie/fix-nix-develop vs origin/main

ruff

Total: 0 on HEAD, 0 on base (➖ 0)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 0 pre-existing issues carried over.

ty (type checker)

Total: 9447 on HEAD, 9447 on base (➖ 0)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 4905 pre-existing issues carried over.

Diagnostics are surfaced as warnings — this check never fails the build.

[alt-glitch]

Duplicate of #33773 — both remove the stale "vercel" group from nix/packages.nix after #33067 removed vercel from pyproject.toml. #33773 is the earlier PR with the same one-line fix.

[ethernet8023]

dupe of #33773