build(deps-dev): bump chai and @types/chai in /contract

Bumps [chai](https://github.com/chaijs/chai) and [@types/chai](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/chai). These dependencies needed to be updated together.

Updates `chai` from 4.2.0 to 4.3.6
- [Release notes](https://github.com/chaijs/chai/releases)
- [Changelog](https://github.com/chaijs/chai/blob/4.x.x/History.md)
- [Commits](chaijs/chai@4.2.0...v4.3.6)

Updates `@types/chai` from 4.2.21 to 4.3.1
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/chai)

---
updated-dependencies:
- dependency-name: chai
  dependency-type: direct:development
  update-type: version-update:semver-minor
- dependency-name: "@types/chai"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]