SDK / exoplayer

- SampleQueue.peek is replaced with SampleQueue.read with
  FLAG_PEEK. This also exposes peek functionality through
  SampleStream.
- Use of DecoderInputBuffer.isFlagsOnly is replaced with
  FLAG_OMIT_SAMPLE_DATA. This flag can be used with or
  without FLAG_PEEK, where-as previously the read position
  would never be advanced for an isFlagsOnly buffer.
- formatRequired is replaced with FLAG_FORMAT_REQUIRED.

PiperOrigin-RevId: 363460105