tests: make smoke-tests Qt6-safe (use QStringLiteral/QLatin1)

Lts/DDS/DdsUnitTestsPlaceholder/ddsFunctionTopicTests_smoke.cpp

@@ -6,15 +6,15 @@ class FunctionTopicSmokeTest : public QObject {
 private slots:
   void test_containers() {
     QStringList list;
-    list << "a" << "b" << "c";
+    list << QStringLiteral("a") << QStringLiteral("b") << QStringLiteral("c");
     QCOMPARE(list.size(), 3);
-    QVERIFY(list.contains("b"));
+    QVERIFY(list.contains(QStringLiteral("b")));
   }
   void test_qmap_basic() {
     QMap<QString,int> m;
-    m["one"] = 1;
-    m["two"] = 2;
-    QCOMPARE(m.value("two"), 2);
+    m[QStringLiteral("one")] = 1;
+    m[QStringLiteral("two")] = 2;
+    QCOMPARE(m.value(QStringLiteral("two")), 2);
   }
 };