Show the window after setting layered attributes in macdrv_UpdateLayeredWindow().
This corresponds to a22dd45a for winex11.drv. Fix a regression from 8892b791, which
called set_window_pos() before calling USER_Driver->pUpdateLayeredWindow().

Fix Active Trader Pro doesn't show splash screen at startup on macOS.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=51984