DocsUI M3: Remove layout variance based on window height

For Material3 the variance will be based only on the window width.

Move layouts/values from `sw` to only `s` and remove the `h600dp`
variant.

Test: Manual build, deploy apk and start it on DUT with flag on
Flag: com.android.documentsui.flags.use_material3
Bug: 380369329
Change-Id: I526b8fd53efe5970bc63e92bddb2978457412deb