h264/h265parse: Don't need to insert SPS/PPS per config-interval if they are in frame

Depending on config-interval property, h264/5 parse insert SPS/PPS nals regardless of existence in current frame. So, in following scenario, every keyframe buffer has double SPS/PPS, since x264 will insert SPS/PPS nal per keyframe by our default setting.

videotestsrc ! x264enc key-int-max=30 ! h264parse config-interval=-1 ! ...