Do not make files in zip disabled in ACTION_VIEW.

Intent.ACTION_VIEW is only used for browsing ZIP files from Downloads.
FragmentTuner should ignore the MIME type from the MIME type filter.

This CL removes the MIME type filtering logic from FilesTuner, as
I believe FilesActivity is never used for picking items, so there should
be no need to mark any files as disabled.

Bug: 28267117
Change-Id: Iba92f82aca60154674a4bea3265b0f1a3ae296dc