fix(i18n): Correctly load OTP-UI's Chinese (simplified) files.

lib/util/i18n.js

@@ -117,6 +117,7 @@ async function loadOtpUiLocaleData(matchedLocale) {
  */
 export async function loadLocaleData(matchedLocale, customMessages) {
   let messages
+  let otpUiLocale = matchedLocale
   switch (matchedLocale) {
     case 'es': // Spanish translation is not specific to a region
       messages = await import('../../i18n/es.yml')
@@ -130,15 +131,18 @@ export async function loadLocaleData(matchedLocale, customMessages) {
     case 'vi': // Vietnamese translation is not specific to a region
       messages = await import('../../i18n/vi.yml')
       break
-    case 'zh': // Chinese translation is not specific to a region
+    case 'zh': // Chinese (Simplified) translation is not specific to a region
       messages = await import('../../i18n/zh.yml')
+      // The OTP-UI files for Chinese (Simplified) are (correclty) named `zh_Hans`.
+      // TODO: Rename this repo's zh files to zh_Hans
+      otpUiLocale = 'zh_Hans'
       break
     default:
       messages = await import('../../i18n/en-US.yml')
       break
   }
 
-  const otpUiMessages = await loadOtpUiLocaleData(matchedLocale)
+  const otpUiMessages = await loadOtpUiLocaleData(otpUiLocale)
 
   // Merge custom strings into the standard language strings.
   const mergedMessages = {