Instead of creating the element first, then setting properties and presets, we gather those and construct the element with the properties. This means users of gst_parse_launch can now set construct-only properties. Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1380 Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3026>