This PR fixes z-indices on all cases for table with and without groups. It also fixes 1px glitches that appeared previously already and also during this refactor, with active and focused rows. The focus on cells is no a portal similar to hovered portal, which works really easily thanks to the z-index management already done on hovered portal. The urgent issues here https://github.com/twentyhq/core-team-issues/issues/1490 have been fixed.