More Sample Table Issues

[sanghoonio]

Per infrastructure meeting today, 11-Mar, there are several issues with the sample table:

1. copying rows from a sample table, or the entire table keeps ph_id column in the clipboard. this affects pasting back into handsontable, because pasting a new ph_id column conflicts with saving in the database
2. when trying to rearrange columns (copying a column and pasting it to a new column, and then removing the old column), saving doesn't actually save the updated order
3. double check schema validation if no schema is selected