Move selectDocument from cleanupFile

The cleanupFile has an additional selectDocument in it that fails when
running different tests. Align the state by moving that deselection into
the individual tests (same behaviour for both tests).

Bug: 412776499
Test: atest com.android.documentsui.FilesActivityUiTest
Flag: com.android.documentsui.flags.use_material3
Change-Id: I0c524d0ddfa63a4f2bb308cb779f7b67ed96affe