Enable ESLint rule jest/no-identical-title (EE-port)

Inactive Accountrequested to merge
winh-jest-no-identical-title-ee into master

EE-port of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/27139

Enable the ESLint rule jest/no-identical-title which is part of jest/recommended.

part of https://gitlab.com/gitlab-org/gitlab-ce/issues/59636

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