CCodecBufferChannel: rendering depth to default to 3

This effectively reverts back to the behavior prior to
Iaa9047387cece811f26e3d9c8ce3d3d4ef8f9ae8 while preserving the server
configurable flag.

Bug: 285871053
Test: presubmit
Change-Id: I08387d44c6c655437e5b9a2deae1e7bfdcc31aa7
1 file changed