configstore: build configstore-utils as header library

This change makes android.hardware.configstore-utils library built as
a header-only library instead of a static library.

Design doc: go/design-confighal
Bug: 35397068
Test: build, run

Change-Id: I59c7c8802aeb1fb687af24cfdb2bbb38723e6221
Merged-In: Idee48816a1a271bdb9ba8cf907d98c3823925da4
1 file changed