Refine face enroll & remove button layout padding

The button include in the security_settings_face.xml
When FaceSettingsRemoveButtonPreferenceController#updateState(),
the margin of Button will be overrided by FooterButtonStyleUtils.
So we should set listPreferredItemPaddingStart or End for Button's
parent view instead.

Test: manual Security > Face Unlock > Delete face model
      > Set up face unlock > Back > Check the button layout
Bug: 202091542
Change-Id: I2b3815f5484ae1e5d256a43b432384e5f0f0f96a