Code Debt: Check `npm run i18n-extract` in CI

[Pinjasaur]

We should have the npm run i18n-extract step ran in CI similarly to linting e.g. fail CI if there are i18n changes that weren't committed.

Rough CI steps:

1. npm run i18n-extract
2. Check if changes e.g. git status --porcelain or git diff --exit-code

• https://remarkablemark.org/blog/2017/10/12/check-git-dirty/
• https://unix.stackexchange.com/questions/155046/determine-if-git-working-directory-is-clean-from-a-script

[Pinjasaur]

Is worth taking into consideration any warnings from the command, too e.g.

warning [FormatJS CLI] Duplicate message id: "BoardTemplateSelector.delete-template", but the `description` and/or `defaultMessage` are different.
warning [FormatJS CLI] Duplicate message id: "DeleteBoardDialog.confirm-info", but the `description` and/or `defaultMessage` are different.