TF-1808: Create func store email when opening in data layer

(cherry picked from commit a24b4698eedd8c28461877a717ef305a6c47f185)

lib/features/email/data/repository/email_repository_impl.dart

@@ -201,6 +201,6 @@ class EmailRepositoryImpl extends EmailRepository {
 
   @override
   Future<void> storeOpenedEmailToCache(Session session, AccountId accountId, DetailedEmail detailedEmail) {
-    throw UnimplementedError();
+    return emailDataSource[DataSourceType.hiveCache]!.storeOpenedEmailToCache(session, accountId, detailedEmail);
   }
 }