This reinstates the permissive behaviour removed by
https://github.com/google/ExoPlayer/commit/fe7e5b8181333683fda7869c3d9cffc0bdefcccb

Test file created by opening bear.opus in a hex editor and naively
duplicating the two header packets, starting at (and including) the
first `OggS` in the file and ending just before the third `OggS`.

#minor-release

Issue: google/ExoPlayer#10038
PiperOrigin-RevId: 452015662
(cherry picked from commit b6b28267)