chore: dplatformhandle tweak

1. check systemtheme is valid
2. typo fix. CreatorWindowEventFile==>WindowCreateEvenFilter

src/kernel/dplatformhandle.cpp

@@ -588,6 +588,9 @@ static void initWindowRadius(QWindow *window)
         return;
 
     auto theme = DGuiApplicationHelper::instance()->systemTheme();
+    if (!theme->isValid())
+        return;
+
     int radius = theme->windowRadius(18); //###(zccrs): 暂时在此处给窗口默认设置为18px的圆角
 
     setWindowProperty(window, _windowRadius, radius);
@@ -604,9 +607,9 @@ static void initWindowRadius(QWindow *window)
     }
 }
 
-class Q_DECL_HIDDEN CreatorWindowEventFile : public QObject {
+class Q_DECL_HIDDEN WindowCreateEvenFilter : public QObject {
 public:
-    CreatorWindowEventFile(QObject *par= nullptr): QObject(par){}
+    WindowCreateEvenFilter(QObject *par= nullptr) : QObject(par){}
 
 public:
     bool eventFilter(QObject *watched, QEvent *event) override {
@@ -657,7 +660,7 @@ bool DPlatformHandle::setEnabledNoTitlebarForWindow(QWindow *window, bool enable
             if (window->handle()) {
                 initWindowRadius(window);
             } else {
-                window->installEventFilter(new CreatorWindowEventFile(window));
+                window->installEventFilter(new WindowCreateEvenFilter(window));
             }
         }