Xwayland with linux_dmabuf v4 feedback support is broken on `WLR_RENDERER=vulkan`
With WLR_RENDERER=vulkan
and Xwayland with xorg/xserver!818 (merged), Xwayland apps can't render anything.
Environment: Arch Linux with wlroots 0.16.1 and sway 1.8, Xwayland xorg/xserver@d67383a6.
Can also reproduce on latest master of wlroots and sway, can't reproduce on xorg/xserver@16e7cdba.