Release v3.17.3 (#1812)

* Prepare release v3.17.3

* Update test fixtures with the new nix-installer version

* flake.lock: Update

Flake lock file updates:

• Updated input 'determinate':
    'https://api.flakehub.com/f/pinned/DeterminateSystems/determinate/3.17.2/019d3290-fc2e-714a-bf96-59b71ef2dcb1/source.tar.gz' (2026-03-28)
  → 'https://api.flakehub.com/f/pinned/DeterminateSystems/determinate/3.17.3/019d691b-0a67-74d9-90e1-1a3c86286399/source.tar.gz' (2026-04-07)
• Updated input 'determinate/determinate-nixd-aarch64-darwin':
    'https://install.determinate.systems/determinate-nixd/tag/v3.17.2/macOS'
  → 'https://install.determinate.systems/determinate-nixd/tag/v3.17.3/macOS'
• Updated input 'determinate/determinate-nixd-aarch64-linux':
    'https://install.determinate.systems/determinate-nixd/tag/v3.17.2/aarch64-linux'
  → 'https://install.determinate.systems/determinate-nixd/tag/v3.17.3/aarch64-linux'
• Updated input 'determinate/determinate-nixd-x86_64-linux':
    'https://install.determinate.systems/determinate-nixd/tag/v3.17.2/x86_64-linux'
  → 'https://install.determinate.systems/determinate-nixd/tag/v3.17.3/x86_64-linux'
• Updated input 'nix':
    'https://api.flakehub.com/f/pinned/DeterminateSystems/nix-src/3.17.2/019d3110-f384-7933-a525-8f854039828f/source.tar.gz' (2026-03-27)
  → 'https://api.flakehub.com/f/pinned/DeterminateSystems/nix-src/3.17.3/019d6913-e8c2-7128-ba76-3dc4f6b58158/source.tar.gz' (2026-04-07)
• Updated input 'nixpkgs':
    'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.969196%2Brev-46db2e09e1d3f113a13c0d7b81e2f221c63b8ce9/019d279e-af65-79ce-92be-5dee7b1e36d4/source.tar.gz' (2026-03-24)
  → 'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.975402%2Brev-68d8aa3d661f0e6bd5862291b5bb263b2a6595c9/019d657b-b3b7-7288-b3c0-42d420df206b/source.tar.gz' (2026-04-05)

* Update Cargo dependencies

* Set Cargo.toml package.version to 3.17.3

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Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]