codecparsers: av1: Add an API to reset the annex_b state only.

codecparsers: av1: Add an API to reset the annex_b state only.

In practice, we encounter streams that have one or more temporal units
error. When that kind of error temporal units is in annex b format, the
whole temporal unit should be discarded.
But the temporal units before it are correct and can be used. More
important, because of the error temporal unit, the parser is in a wrong
state and all later temporal unit are also parsed uncorrectly.
We need to add this API to reset the annex_b state only when we meet
some temporal unit error.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1464>