xwayland/eglstream: Drop xwl_eglstream_set_window_pixmap
Not sure why we'd need to abandon a pending stream for a pixmap just because it's no longer a window pixmap. Let's try not to.
Plus simplify pending stream callback destruction.
Not sure why we'd need to abandon a pending stream for a pixmap just because it's no longer a window pixmap. Let's try not to.
Plus simplify pending stream callback destruction.