Fixes GROUPBY+ HSTACK value field headers

Groupby_Retitle.lambda

/*
Name: GROUPBY_RETITLE
Description: Replaces the native (GROUPBY+HSTACK) value field headers with provided [custom_headers] array.
 GROUPBY.[Field_headers] must equal 2 or 3.
Made By: Medohh2120
*/

GROUPBY_RETITLE = LAMBDA(groupby_result, [custom_headers],
    LET(
        n_value_fields, SUM(--(TAKE(groupby_result, 1) <> "")),
        n_row_fields, COLUMNS(groupby_result) - n_value_fields,
        row_fields_fields, DROP(TAKE(groupby_result, , n_row_fields), 1),
        default_headers, TAKE(groupby_result, 1, -n_value_fields),
        grid, DROP(groupby_result, 2, n_row_fields),
        IF(
            ISOMITTED(custom_headers),
            HSTACK(row_fields_fields, VSTACK(default_headers, grid)),
            HSTACK(row_fields_fields, VSTACK(custom_headers, grid))
        )
    )
);

GROUPBY.[Field_headers] = 3

GROUPBY.[Field_headers] = 2