In GStreamer that buffer information is decoupled, holding other structures to
describe the stream: GstCaps. So, to keep the GStreamer design this patch
removes these information from GstVulkanEncoderPicture and pass to
gst_vulkan_encoder_encode() a pointer to GstVideoInfo.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8007>