ci: Remove nix check

It was breaking a lot, due to Cargo dependencies not being published,
no surprise there, we are just publishing them with the changes it is
complaining about.

Author: cdecker

.github/workflows/ci.yaml

@@ -594,25 +594,6 @@ jobs:
           cat config.vars
           VALGRIND=0 uv run eatmydata pytest tests/ -vvv -n ${PYTEST_PAR} ${PYTEST_OPTS}
 
-  check-flake:
-    name: Check Nix Flake
-    runs-on: ubuntu-22.04
-    strategy:
-      fail-fast: true
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-        with:
-          submodules: "recursive"
-      - name: Check Nix flake inputs
-        uses: DeterminateSystems/flake-checker-action@v12
-      - name: Install Nix
-        uses: cachix/install-nix-action@V31
-        with:
-          nix_path: nixpkgs=channel:nixos-25.05
-      - name: Check flake
-        run: nix flake check .?submodules=1#
-
   gather:
     # A dummy task that depends on the full matrix of tests, and
     # signals successful completion. Used for the PR status to pass
@@ -625,7 +606,6 @@ jobs:
       - integration-valgrind
       - integration-sanitizers
       - min-btc-support
-      - check-flake
     if: ${{ always() }}
     steps:
       - name: Complete