Duplicate locale in page during creation

[psykzz]

https://github.com/microapps/gatsby-plugin-react-i18next/blob/0cb31fe4e48dd5b1771efaf24c85ece5540aa084/src/plugin/onCreatePage.ts#L98C7-L110

Locale is being set twice when it creates new pages, leading to /en-us/en-us/page (and more).