DocsUI: Mark testMoveDirRecursively_loadingInFirstCursor as large

This test is sometimes observed to take over 1 minute to run, causing
failures in presubmit, so mark it accordingly.

Bug: 43214822
Test: atest -c 'DocumentsUIGoogleTests:com.android.documentsui.services.MoveJobTest'
Flag: TEST_ONLY
Change-Id: I391a4c580f4235bb7ebdea4ccb8bd21f37737f5a