Remove flag and version from CSD of APV.

As encoder is creating CSD without version and flag,
CSD should follow same pattern in case of setting CSD
from extractor and ignore first four byte of version and flag
which comes from FullBox. CSD will only have the
ApvDecoderConfigurationBox data.

Bug: 391716515
Bug: 392976813
Bug: 392976819
Test: atest MediaExtractorTest
Change-Id: If761576be822bbdd2395f6d7fb99a9d72b7322f4