build(deps): bump dd-trace from 3.20.0 to 4.16.0 in /backend

Bumps [dd-trace](https://github.com/DataDog/dd-trace-js) from 3.20.0 to 4.16.0.
- [Release notes](https://github.com/DataDog/dd-trace-js/releases)
- [Commits](DataDog/dd-trace-js@v3.20.0...v4.16.0)

---
updated-dependencies:
- dependency-name: dd-trace
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>