[fenix] For https://github.com/mozilla-mobile/fenix/issues/7559 - fixes 2 issues:

- The same item now doesn't recreate the activity
- The app context now contains the right locale

app/src/main/java/org/mozilla/fenix/settings/advanced/DefaultLocaleSettingsController.kt

@@ -21,17 +21,23 @@ class DefaultLocaleSettingsController(
 ) : LocaleSettingsController {
 
     override fun handleLocaleSelected(locale: Locale) {
-        if (localeSettingsStore.state.selectedLocale == locale) {
+        if (localeSettingsStore.state.selectedLocale == locale &&
+            !LocaleManager.isDefaultLocaleSelected(context)) {
             return
         }
         localeSettingsStore.dispatch(LocaleSettingsAction.Select(locale))
         LocaleManager.setNewLocale(context, locale.toLanguageTag())
+        LocaleManager.updateBaseConfiguration(context, locale)
         (context as Activity).recreate()
     }
 
     override fun handleDefaultLocaleSelected() {
+        if (LocaleManager.isDefaultLocaleSelected(context)) {
+            return
+        }
         localeSettingsStore.dispatch(LocaleSettingsAction.Select(localeSettingsStore.state.localeList[0]))
         LocaleManager.resetToSystemDefault(context)
+        LocaleManager.updateBaseConfiguration(context, localeSettingsStore.state.localeList[0])
         (context as Activity).recreate()
     }
 

app/src/main/java/org/mozilla/fenix/settings/advanced/LocaleManagerExtension.kt

@@ -51,3 +51,15 @@ fun LocaleManager.getSelectedLocale(
 fun LocaleManager.isDefaultLocaleSelected(context: Context): Boolean {
     return getCurrentLocale(context) == null
 }
+
+/**
+ * Update the locale for the configuration of the app context's resources
+ */
+@Suppress("DEPRECATION")
+fun LocaleManager.updateBaseConfiguration(context: Context, locale: Locale) {
+    val resources = context.applicationContext.resources
+    val config = resources.configuration
+    config.setLocale(locale)
+    config.setLayoutDirection(locale)
+    resources.updateConfiguration(config, resources.displayMetrics)
+}