Pontoon: Update French (fr) localization of Firefox Monitor Website

Localization authors:
- Théo Chevalier <theo.chevalier11@gmail.com>

locales/fr/app.ftl

@@ -8,6 +8,7 @@
 -brand-name = Firefox
 -brand-Quantum = Firefox Quantum
 -brand-Mozilla = Mozilla
+-brand-HIBP = Have I Been Pwned
 layout-Firefox = { -brand-name }
 # Descriptive headline for a column of links where users can give feedback, or get additional information about, Firefox Monitor.
 layout-support = Assistance