✨(react) fix translations and add missing translations

This commit improves the translations method to handle undefined values
gracefully and adds several missing translations for modals in the
French locale.

packages/react/src/components/Provider/index.tsx

@@ -47,7 +47,10 @@ const findTranslation = (
   locale: TranslationSet,
 ): string | undefined => {
   const [namespace, ...keys] = key.split(".");
-  return keys.reduce((acc, subKey) => acc[subKey], (locale as any)[namespace]);
+  return keys.reduce(
+    (acc, subKey) => acc?.[subKey],
+    (locale as any)[namespace],
+  );
 };
 
 export const CunninghamProvider = ({