MediaMuxer: Create FullBox for APV

APV box extends ISOBMFF `FullBox`. `FullBox` has extra 32 bits of
data containing flag and version. Thus, added 4 byte data in apvC
box creation.

Bug: 392976813
Bug: 392976819
Test: atest MediaMuxerTest
Change-Id: I703e3e7b6e5515bd777a227c8ca11f4a1ff48ba7