This is going to be used when the pool is used by a video decoder for VK_IMAGE_USAGE_VIDEO_DECODE_DST_BIT_KHR, since the frame allocation needs the VkVideoProfileInfoKHR, and for that here GstCaps is used to wire it. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4351>