TF-3885 Fix language defaults

Signed-off-by: dab246 <tdvu@linagora.com>

lib/features/composer/presentation/extensions/create_email_request_extension.dart

@@ -158,7 +158,7 @@ extension CreateEmailRequestExtension on CreateEmailRequest {
             IndividualHeaderIdentifier.acceptLanguageHeader: LocalizationService.supportedLocalesToLanguageTags()
           },
           contentLanguageHeader: {
-            IndividualHeaderIdentifier.contentLanguageHeader: LocalizationService.getLocaleFromLanguage().toLanguageTag()
+            IndividualHeaderIdentifier.contentLanguageHeader: LocalizationService.getInitialLocale().toLanguageTag()
           },
         )
       },

lib/features/email/presentation/controller/single_email_controller.dart

@@ -2156,7 +2156,7 @@ class SingleEmailController extends BaseController with AppLoaderMixin {
         {_displayingEventBlobId!},
         emailId,
         session!.getLanguageForCalendarEvent(
-          LocalizationService.getLocaleFromLanguage(),
+          LocalizationService.getInitialLocale(),
           accountId!,
         ),
       ));
@@ -2177,7 +2177,7 @@ class SingleEmailController extends BaseController with AppLoaderMixin {
         {_displayingEventBlobId!},
         emailId,
         session!.getLanguageForCalendarEvent(
-          LocalizationService.getLocaleFromLanguage(),
+          LocalizationService.getInitialLocale(),
           accountId!,
         ),
       ));
@@ -2198,7 +2198,7 @@ class SingleEmailController extends BaseController with AppLoaderMixin {
         {_displayingEventBlobId!},
         emailId,
         session!.getLanguageForCalendarEvent(
-          LocalizationService.getLocaleFromLanguage(),
+          LocalizationService.getInitialLocale(),
           accountId!,
         ),
       ));

lib/features/manage_account/presentation/language_and_region/language_and_region_controller.dart

@@ -38,9 +38,10 @@ class LanguageAndRegionController extends BaseController {
 
   @override
   void handleSuccessViewState(Success success) {
-    super.handleSuccessViewState(success);
     if (success is SaveLanguageSuccess) {
-      LocalizationService.changeLocale(success.localeStored.languageCode);
+      LocalizationService.changeLocale(success.localeStored);
+    } else {
+      super.handleSuccessViewState(success);
     }
   }