DocumentsUI: Duplicate layout folder to be behind flag M3 enabled

This folder was left behind by accident on previous CL ag/30392873.

Test: Manual build, deploy apk and start it on DUT with flag on/off
Flag: com.android.documentsui.flags.use_material3
Bug: 377771271, 380369329
Change-Id: I688531b8bb18a919ac19951a735cdee330a9c16c