When a TD is being processed, it is not always pushed immediatly. Resetting
the time information lead to lost of timestamp in TU to Frame conversion. The
TU would be formed by buffer of [TD][Frame], and the timestamp taken from
the TU buffer was lost then the TD was handled.
The handling of TS should be entirely done by the 3 functions:
- gst_av1_parse_handle_obu_to_obu() (direct input to output)
- gst_av1_parse_handle_to_big_align() Reset DTS on detected TU or TD
- gst_av1_parse_handle_to_small_and_equal_align() PTS on show frame, flat DTS
Fixes: 79312357a6
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8026>