build(deps): bump braze-specification from d45ddeb to 4b640a8

Bumps [braze-specification](https://github.com/braze-community/braze-specification) from `d45ddeb` to `4b640a8`.
- [Release notes](https://github.com/braze-community/braze-specification/releases)
- [Commits](braze-community/braze-specification@d45ddeb...4b640a8)

---
updated-dependencies:
- dependency-name: braze-specification
  dependency-type: direct:production
...

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