Direct scanout doesn't work in 5.23

I'm using the nvidia beta driver 495.29.05, along with egl-wayland 1.19 and latest xwayland git. This is on KWin 5.23.1 with this MR on top.

Basically direct scanout doesn't work due to !1295 (merged), at least on an Nvidia gpu.

Specifically this change, where !m_outputs[screen].output->directScanoutInhibited() was changed to output->directScanoutInhibited(). Reverting that allows pure wayland windows to successfully scanout according to kwin debug logs.

After that Xwayland scanout still won't work due to this issue.