fix(app/DefaultTranslator): display correctly qt messages

tests/src/app/DefaultTranslator.cpp

@@ -27,12 +27,9 @@ QString DefaultTranslator::translate (
   const char *disambiguation,
   int n
 ) const {
-  if (!m_contexts.contains(context))
-    return "";
-
   QString translation = QTranslator::translate(context, source_text, disambiguation, n);
 
-  if (translation.length() == 0)
+  if (translation.length() == 0 && m_contexts.contains(context))
     qWarning() << QStringLiteral("Unable to find a translation. (context=%1, label=%2)")
       .arg(context).arg(source_text);