[DocsUI M3] Dupliate drawable resources for M3 eanbled

res/drawable* folders includes some colors which we need to
update for M3 uplfit. This CL duplicates the res/drawable and
res/drawable-ldrtl into
res/flag(com.android.documentsui.flags.use_material3) folder.

Bug: 377771271
Test: build, deploy DocsUI and start it on DUT with flag on/off
Flag: com.android.documentsui.flags.use_material3
Change-Id: Iee992ef8d2b14df0035c3f592366b609a9ed977d