calculatorrunner: Fix superscripted numbers

Use toLocal8Bit instead of toLatin1 see https://doc.qt.io/qt-5/qstring.html#toLatin1.
Otherwise the superscripted numbers would not be correctly converted.

BUG: 435932

runners/calculator/autotests/calculatorrunnertest.cpp

@@ -50,6 +50,8 @@ void CalculatorRunnerTest::testQuery_data()
     QTest::newRow("x as multiplication sign") << "25x4" << "100";
 #ifdef ENABLE_QALCULATE
     QTest::newRow("single digit factorial") << "5!" << "120";
+    QTest::newRow("superscripted number") << "2³"
+                                          << "8"; // BUG: 435932
 #endif
 
     QTest::newRow("hex to decimal lower case") << "0xf" << "15";

runners/calculator/qalculate_engine.cpp

@@ -85,7 +85,8 @@ QString QalculateEngine::evaluate(const QString &expression, bool *isApproximate
     }
 
     QString input = expression;
-    QByteArray ba = input.replace(QChar(0xA3), "GBP").replace(QChar(0xA5), "JPY").replace('$', "USD").replace(QChar(0x20AC), "EUR").toLatin1();
+    // Make sure to use toLocal8Bit, the expression can contain non-latin1 characters
+    QByteArray ba = input.replace(QChar(0xA3), "GBP").replace(QChar(0xA5), "JPY").replace('$', "USD").replace(QChar(0x20AC), "EUR").toLocal8Bit();
     const char *ctext = ba.data();
 
     CALCULATOR->terminateThreads();