kcmkwin/scripts: fix a warning

Summary:
Prevents warnings such as :
org.kde.kcoreaddons: Expected JSON property "X-KWin-Exclude-Listing" to be a single string. but it is a bool

Reviewers: #kwin, ervin, bport, cross, hchain, zzag

Reviewed By: #kwin, zzag

Subscribers: zzag, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D28018

kcmkwin/kwinscripts/module.cpp

@@ -126,10 +126,7 @@ void Module::importScriptInstallFinished(KJob *job)
 void Module::updateListViewContents()
 {
     auto filter =  [](const KPluginMetaData &md) {
-        if (md.value(QStringLiteral("X-KWin-Exclude-Listing")) == QLatin1String("true") ) {
-            return false;
-        }
-        return true;
+        return !md.rawData().value("X-KWin-Exclude-Listing").toBool();
     };
 
     const QString scriptFolder = QStringLiteral("kwin/scripts/");