Stripe elements should be in the same language as the site

Currently, the Credit Card fields displayed by Stripe are always in English.

Stripe supports the following languages: ar, da, de, en, es, fi, fr, he, it, ja, lt, lv, ms, nl, no, pl, pt, ru, sv, zh (https://stripe.com/docs/stripe-js/reference).

There is a locale param available for the Stripe object that we can use:

stripe = Stripe(CRM.vars.stripe.publishableKey, {locale: 'fr'});

Example:

I'll try to see if we can add a locale variable to CRM.vars.stripe, if the locale is supported by Stripe.