C2Config: allow component to signal support for buffer fences

The added API feature is for components to signal that they can handle
fences for blocks regardless of how they are being received. (Whether
a block is received from a work, or fetched from any block pool.)

Bug: 373819294
Test: presubmit
Change-Id: Id0daeb20fcea520a1c83c96c1a31f05850c0d405