example: Do not set windowDimming = false in demo app

Author: YuKongA

composeApp/src/commonMain/kotlin/UITest.kt

@@ -230,8 +230,7 @@ fun UITest(
                         alignment = PopupPositionProvider.Align.BottomRight,
                         onDismissRequest = {
                             isBottomPopupExpanded.value = false
-                        },
-                        windowDimming = false
+                        }
                     ) {
                         ListPopupColumn {
                             items.take(3).forEachIndexed { index, navigationItem ->