feat(vdev): add stderr to output

[thomasqueirozb]

Summary

Several improvements to VDEV error handling.

Vector configuration

NA

How did you test this PR?

license_tool="$(which dd-rust-license-tool)"
mv "$license_tool" "$license_tool.bak"

cargo vdev build licenses
# You should see the following output:
# Error: Failed to spawn process "dd-rust-license-tool" "write"
# 
# Caused by:
#     No such file or directory (os error 2)

# Now we write a failing script into the license tool
echo -e '#!/bin/sh\necho "I am stdout"; >&2 echo "I am stderr"; exit 1' > "$license_tool"
chmod +x "$license_tool"

cargo vdev build licenses

# You should see the following output:
# Error: Failed to spawn process "dd-rust-license-tool" "write"
# failed with exit code: 1
# 
# output:
# I am stdout
# I am stderr

mv "$license_tool.bak" "$license_tool"

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.