Remove an if condition no longer necessary

Signed-off-by: falkTX <falktx@falktx.com>

dgl/src/WindowPrivateData.cpp

@@ -639,8 +639,7 @@ void Window::PrivateData::onPuglConfigure(const double width, const double heigh
     const uint uwidth = static_cast<uint>(width + 0.5);
     const uint uheight = static_cast<uint>(height + 0.5);
 
-    if (self != nullptr)
-        self->onReshape(uwidth, uheight);
+    self->onReshape(uwidth, uheight);
 
 #ifndef DPF_TEST_WINDOW_CPP
     if (topLevelWidget != nullptr)