Update config.{sub,guess} after extraction

It can still be enabled manually in the preferences as in previous
versions. Only it will not be used with the default ("auto") setting.

breaks with IV in first packet as pointed out by funman
This reverts commit ccc273b4.

IOD bytes must be read in order.
introduced by 8fdf1f20

both packetizer and codec requiring extra

We might need to generate Opus headers without actually encoding anything