Don't show autofill settings if not enabled

The non-indexable keys of language-and-input on my angler are:
  game_controller_settings_category, gesture_assist,
  gesture_double_tap_screen, default_autofill

Fixes: 35956220
Test: Disabled auto-fill and looked at settings: did not find
      autofill button and could not find auto-fill in search
      Settings robolectric test
Merged-In: I0923e707422d1b1de5153a63fa3a5fe4773c055d
Change-Id: I0923e707422d1b1de5153a63fa3a5fe4773c055d