chore(ci): move changelog fragment validation to vdev/Rust

[pront]

Summary

Move changelog validation to vdev.

(We leverage bininstall for vdev now)

In the future we can also rewrite the relevant scripts/generate-release-cue.rb bits in Rust.

Vector configuration

How did you test this PR?

• Validates: https://github.com/vectordotdev/vector/actions/runs/17444938058?pr=23702
• Fails: https://github.com/vectordotdev/vector/actions/runs/17444875792/job/49536759416?pr=23702

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

Notes

• Please read our Vector contributor resources.
• Do not hesitate to use @vectordotdev/vector to reach out to us regarding this PR.
• Some CI checks run only after we manually approve them.
  • We recommend adding a pre-push hook, please see this template.
  • Alternatively, we recommend running the following locally before pushing to the remote branch:
    • cargo fmt --all
    • cargo clippy --workspace --all-targets -- -D warnings
    • cargo nextest run --workspace (alternatively, you can run cargo test --all)
• After a review is requested, please avoid force pushes to help us review incrementally.
  • Feel free to push as many commits as you want. They will be squashed into one before merging.
  • For example, you can run git merge origin master and git push.
• If this PR introduces changes Vector dependencies (modifies Cargo.lock), please
  run cargo vdev build licenses to regenerate the license inventory and commit the changes (if any). More details here.

[datadog-vectordotdev]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

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[thomasqueirozb]

Reminder: this change needs to be reverted before merging