Write animation speed to kdeglobals

When the animation slider moved to look and feel a UI was kept within
the compositing KCM that was only visible for non Plasma users so they
still had a way to access this.

This non-plasma version still wrote to kwinrc. In theory this was fine
unless you used both. We also hit an issue where a stray
m_settings->save() call in `reenableGl` would sync the settings to the
wrong place.

This patch moves everything to write to kdeglobals and cleans up any old
entries here.

BUG: 431259

src/kcmkwin/kwincompositing/main.cpp

@@ -69,6 +69,10 @@ KWinCompositingKCM::KWinCompositingKCM(QWidget *parent, const QVariantList &args
     , m_settings(new KWinCompositingSetting(this))
 {
     m_form.setupUi(this);
+
+    // AnimationDurationFactor should be written to the same place as the lnf to avoid conflicts
+    m_settings->findItem("AnimationDurationFactor")->setWriteFlags(KConfigBase::Global | KConfigBase::Notify);
+
     addConfig(m_settings, this);
 
     m_form.glCrashedWarning->setIcon(QIcon::fromTheme(QStringLiteral("dialog-warning")));
@@ -211,6 +215,9 @@ void KWinCompositingKCM::save()
 
     KCModule::save();
 
+    // This clears up old entries that are now migrated to kdeglobals
+    KConfig("kwinrc", KConfig::NoGlobals).group("KDE").revertToDefault("AnimationDurationFactor");
+
     // Send signal to all kwin instances
     QDBusMessage message = QDBusMessage::createSignal(QStringLiteral("/Compositor"),
                                                       QStringLiteral("org.kde.kwin.Compositing"),