build(deps): Bump cachix/install-nix-action from V28 to 29

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from V28 to 29. This release includes the previously tagged commit.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](cachix/install-nix-action@V28...v29)

---
updated-dependencies:
- dependency-name: cachix/install-nix-action
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/e2e.yml

@@ -38,7 +38,7 @@ jobs:
       # Install nix using cachix/install-nix-action if running on ARC runners
       # See: https://github.com/DeterminateSystems/nix-installer-action/issues/68
       - name: Install Nix on self-hosted ARC runners
-        uses: cachix/install-nix-action@V28
+        uses: cachix/install-nix-action@v29
         if: inputs.runs-on == 'self-hosted-ncn-dind'
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}