[FIX] web: reset 'invisible' table cells to correct display

Make sure '.o_invisible_modifier' table-cells are forced back to
`display: table-cell` to keep correct alignement. Indeed using the
`initial` value forced them to `inline` instead (creating some
obvious visual bugs in some cases).

addons/web/static/src/less/list_view.less

@@ -100,7 +100,9 @@
     }
 
     .o_data_cell.o_invisible_modifier {
-        display: initial!important;  // Override invisible to keep the cells aligned
+        // Override display: none to keep table cells aligned. Note: cannot use
+        // 'initial' as it will force them to 'inline', not 'table-cell'.
+        display: table-cell!important;
     }
 
     //--------------------------------------------------------------------------