MediaCodec: Migrate away from IGBC

We're no longer supporting client use of IGBP/IGBC. This CL replaces
usage in MediaCodec.cpp with BufferItemConsumer.

BYPASS_IGBP_IGBC_API_REASON=warren buffers

Bug: 393639153
Flag: com.android.graphics.libgui.flags.wb_media_migration
Test: atest MediaCodecTest
Change-Id: I36b6f18f117c6f649063928f958114a8811185d5