Examples: Fix reading the category ordering from manifest

qtcreator_tutorials.xml contains ordering information for the tutorials,
and if we read that (first) we ignore any subsequent ordering that the
set of Qt examples defines (in qtdoc/examples-manifest.xml).

Only read the tutorials.xml if we are actually interested in tutorials.

Amends 08bbe885b4

Change-Id: I9148cc9f1060500f46be2bbc9c9ef6c2512c2f6c
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Kai Köhne <kai.koehne@qt.io>

src/plugins/qtsupport/exampleslistmodel.cpp

@@ -363,7 +363,8 @@ void ExamplesViewController::updateExamples()
 
     const QStringList sources = m_exampleSetModel->exampleSources(&examplesInstallPath,
                                                                   &demosInstallPath,
-                                                                  &qtVersion);
+                                                                  &qtVersion,
+                                                                  m_isExamples);
     QStringList categoryOrder;
     QList<ExampleItem *> items;
     for (const QString &exampleSource : sources) {
@@ -493,12 +494,15 @@ QtVersion *ExampleSetModel::findHighestQtVersion(const QtVersions &versions) con
 
 QStringList ExampleSetModel::exampleSources(QString *examplesInstallPath,
                                             QString *demosInstallPath,
-                                            QVersionNumber *qtVersion)
+                                            QVersionNumber *qtVersion,
+                                            bool isExamples)
 {
     QStringList sources;
 
+    if (!isExamples) {
         // Qt Creator shipped tutorials
         sources << ":/qtsupport/qtcreator_tutorials.xml";
+    }
 
     QString examplesPath;
     QString demosPath;

src/plugins/qtsupport/exampleslistmodel.h

@@ -41,7 +41,8 @@ public:
     bool selectExampleSet(int index);
     QStringList exampleSources(QString *examplesInstallPath,
                                QString *demosInstallPath,
-                               QVersionNumber *qtVersion);
+                               QVersionNumber *qtVersion,
+                               bool isExamples);
     bool selectedQtSupports(const Utils::Id &target) const;
 
 signals: