Update the Pick and Save bottom bars for material 3

There are a few changes made outside the normal realm of a resyle:

  - The R.layout.fragment_pick has been updated to use a
    ConstraintLayout. This was done as the FrameLayout was not playing
    nice with the right alignment of the buttons. The FrameLayout is
    used for intercepting clicks when the button is disabled.
  - The R.layout.fragment_save currently has a text field and a single
    button. When the second "Cancel" button is added it takes almost
    50% of the width on a mobile device. To avoid this, let's not
    include the Cancel button on <600dp layouts only on FEATURE_PC
    devices.

Bug: 381929144
Test: m DocumentsUIGoogle && manual inspection
Flag: com.android.documentsui.flags.use_material3

Change-Id: Ib95c5731a1ea78276f542ff9b31d89c65ba1a52b