Backport of "vah26{4,5}enc: Set DTS offset before PTS" into 1.24
requested to merge gstreamer-backport-bot/gstreamer:mr-6791-backport-into-1.24-DTS_H264_H265 into 1.24
Backport of !6791 (merged) "vah26{4,5}enc: Set DTS offset before PTS".
Commits: