ci: disable FlakeHub access for Nix builds

It's flaky and not necessary.

Author: sangwa

.github/workflows/release.yml

@@ -12,7 +12,6 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       contents: read
-      id-token: write
     steps:
       - name: Checkout
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2