chore(opentelemetry): Update protobuf definitions to 1.4.0

[bruceg]

Summary

As the title says, updates the otel protobuf definitions to 1.4.0. v1.5.0 adds additional fields that need some less trivial code changes so I decided to stop here.

References

• chore(vdev): Add subcommand to update protobuf definitions #26470

Vector configuration

N/A

How did you test this PR?

N/A none of the added fields are used yet

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.

Contributor Guidelines

• Please read our Vector contributor resources.
• Do not hesitate to use @vectordotdev/vector to reach out to us regarding this PR.
• Before pushing, follow our pre-push guidance.
• 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.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-29T22:44:41.864905Z	1538b0b	PR opened

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

[datadoghq-integration]

More details

The new OTLP Metric metadata and Span/Link flags use previously unused field numbers, while affected Rust constructors supply empty or zero defaults, preserving existing encode/decode behavior.

Was this helpful? React 👍 or 👎

_{Open Bits AI session}

_{🤖 Bits Code Review · Commit 1538b0b · @DataDog review to ask questions}