Move board_spec from karma to jest.

Summary

Refactor board_spec from karma to jest.

/cc @pslaughter

Improvements

Removing karma.

Risks

None.

Involved components

• https://gitlab.com/gitlab-org/gitlab/blob/master/spec%2Fjavascripts%2Fboards%2Fcomponents%2Fboard_spec.js

Optional: Intended side effects

None

Optional: Missing test coverage