[Windows] Take initial flags into account when creating main window.

platform/windows/display_server_windows.cpp

@@ -4237,7 +4237,7 @@ DisplayServerWindows::DisplayServerWindows(const String &p_rendering_driver, Win
 		window_position = screen_get_position(p_screen) + (screen_get_size(p_screen) - p_resolution) / 2;
 	}
 
-	WindowID main_window = _create_window(p_mode, p_vsync_mode, 0, Rect2i(window_position, p_resolution));
+	WindowID main_window = _create_window(p_mode, p_vsync_mode, p_flags, Rect2i(window_position, p_resolution));
 	ERR_FAIL_COND_MSG(main_window == INVALID_WINDOW_ID, "Failed to create main window.");
 
 	joypad = new JoypadWindows(&windows[MAIN_WINDOW_ID].hWnd);