In case of re-syncing (i.e. moving to another partition to avoid too much of an interleave), there was previously no checks to figure out whether a given partition was already fully handled (i.e. when coming across it again after a previous resync). In order to handle this at least for single-track partitions, check whether we have reached the essence track duration, and if so skip the partition. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2150>