[DocsUI M3] Move drawable resources for flag M3 disabled

res/drawable* folders includes some colors which we need to
update for M3 uplfit. This CL moves 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: I30f83cd2e4f7520ccb90e1ece595d26d86826e75