lv: use brackets for invisible devices when formatting device segments

lv: use brackets for invisible devices when formatting device segments

Include brackets for the name if the dev is invisible.
This change applies to all callers of _format_pvsegs fn:
  - lvseg_devices (the "lvs -o devices")
  - lvseg_metadata_devices (the "lvs -o metadata_devices)
  - lvseg_seg_pe_ranges (the "lvs -o seg_pe_ranges")
  - lvseg_seg_metadata_le_ranges (the "lvs -o seg_metadata_le_ranges")