[Qt6] Try to fix

src/bin/model/subtitlemodel.cpp

@@ -180,7 +180,7 @@ void SubtitleModel::importSubtitle(const QString &filePath, int offset, bool ext
 #else
         std::optional<QStringConverter::Encoding> inputEncoding = QStringConverter::encodingForName(encoding.data());
         if (inputEncoding) {
-            stream.setEncoding(inputEncoding);
+            stream.setEncoding(inputEncoding.value());
         }
         // else: UTF8 is the default
 #endif
@@ -248,7 +248,7 @@ void SubtitleModel::importSubtitle(const QString &filePath, int offset, bool ext
 #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
         stream.setCodec(QTextCodec::codecForName(encoding));
 #else
-        stream.setEncoding(QStringConverter::encodingForName(encoding.data()));
+        stream.setEncoding(QStringConverter::encodingForName(encoding.data()).value());
 #endif
         QString line;
         qDebug() << " correct ass file  " << filePath;