* Fix require-unicode-regexp issues
See [`require-unicode-regexp`](https://eslint.org/docs/rules/require-unicode-regexp) for more information.
This change enables `require-unicode-regexp` and fixes the issues raised by the rule.
* Remove case-insensitive flag from regexps
This test mirrors the `localization` integration test. It only tests
the display of fiat currency on the home page, and it only tests one
currency (`php`).
