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.
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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.