fix: broken save on empty row existance

[rtdany10]

Peek.2023-05-08.17-07.mp4

Problem:
Unable to save the document if the first save action was initiated with an empty row. Why leave the first row empty? Cause of multi select.

Cause:

• remove_empty_rows uses get_all_docs to fetch the child table rows.
• get_all_docs loops the document and if any key(field) is an array, treats it as a table
• _calculate_taxes_and_totals adds a new key _items to the doc.
• _items is not an actual table, but a clone of the actual items field.
• get_all_docs treats _items and items as different table causing duplicated rows
• Trying to clear this duplicate empty row throws an error and takes away the user's ability to save.

[rtdany10]

Introduced via: #33874

[rtdany10]

@ruthra-kumar @deepeshgarg007 @marination

[ruthra-kumar]

LGTM