chore(deps): bump mockito from 5.3.2 to 5.4.0

Bumps [mockito](https://github.com/dart-lang/mockito) from 5.3.2 to 5.4.0.
- [Release notes](https://github.com/dart-lang/mockito/releases)
- [Changelog](https://github.com/dart-lang/mockito/blob/master/CHANGELOG.md)
- [Commits](dart-lang/mockito@5.3.2...5.4.0)

---
updated-dependencies:
- dependency-name: mockito
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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