Bump third_party/perfetto/repo from b9aca8f to c478eb8

Bumps [third_party/perfetto/repo](https://github.com/google/perfetto) from `b9aca8f` to `c478eb8`.
- [Release notes](https://github.com/google/perfetto/releases)
- [Commits](google/perfetto@b9aca8f...c478eb8)

---
updated-dependencies:
- dependency-name: third_party/perfetto/repo
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>