Fix icons on Windows

KirigamiApp currently calls KIconTheme::initTheme too late for Windows,
as a workaround we can go back to calling it ourselves.

(cherry picked from commit a02a04d966)

src/app/main.cpp

@@ -33,6 +33,7 @@
 #include <KWindowSystem>
 #endif
 
+#include <KIconTheme>
 #include <KLocalizedQmlContext>
 #include <KLocalizedString>
 #include <KirigamiApp>
@@ -102,6 +103,10 @@ int main(int argc, char *argv[])
 {
     QNetworkProxyFactory::setUseSystemConfiguration(true);
 
+    // We currently need to do this ourselves,
+    // KirigamiApp currently called this after constructing the app which breaks icons on Windows.
+    KIconTheme::initTheme();
+
 #ifdef HAVE_WEBVIEW
     QtWebView::initialize();
     QCoreApplication::setAttribute(Qt::AA_ShareOpenGLContexts);