[AlwaysOnTop] Round corners on Windows 11 (#19109)

* check window corners

* draw rounded rectangle

* draw rounded corners

* switch between rounded and not rounded rects

* added enabled corners setting

* update corner

src/modules/alwaysontop/AlwaysOnTop/WindowCornersUtil.h

@@ -0,0 +1,4 @@
+namespace WindowBordersUtils
+{
+    bool AreCornersRounded(HWND window) noexcept;
+}