Improve scalar functions in ORDER BY unparsing

[sgrebnov]

Which issue does this PR close?

Improves unparsing to correctly handle scalar functions in ORDER BY. If SELECT and ORDER BY contain the same expression with a scalar function, the ORDER BY expression will be replaced by a Column expression (e.g., "substr(customer.c_last_name, Int64(0), Int64(5))"), and we need to transform it back to the actual expression. This is done for scalar function expressions only.

  select c_last_name,c_first_name, substr(c_last_name,0,5)
  from customer
  order by substr(c_last_name,0,5)
  limit 10;

Before

select
	"customer"."c_last_name",
	"customer"."c_first_name",
	substr("customer"."c_last_name",0,5)
from
	"customer"
order by
	"substr(customer.c_last_name,Int64(0),Int64(5))" asc nulls last
limit 10

After

select
	"customer"."c_last_name",
	"customer"."c_first_name",
	substr("customer"."c_last_name",0,5)
from
	"customer"
order by
	substr("customer"."c_last_name",0,5) asc nulls last
limit 10

Foxes TPC-DS Benchmark Q85, Q79

Closes spiceai/spiceai#2962

ORDER BY `substr(reason.r_reason_desc,Int64(1),Int64(20))`