Move libgiftranscode.so to /product

libgiftranscode.so is a jni lib for Messaging app, which is usually
overridden by proprietary apps on shipping devices. We have moved
Messaging to /product. Now this CL move libgiftranscode.so too.

Bug: 138282284
Test: Open gif files with Messaging on aosp_crosshatch
Change-Id: Ic104ba8ec5c2258a28c8d19151a00f6c601b5f80