Improve unparsing to handle aggregations with grouping set

[sgrebnov]

Which issue does this PR close?

PR improves Aggregation unparsing logic to handle plans with grouping sets. When Aggregation is created (below) grouping_set_to_exprlist is used to retrieve grouping set expressions and populate schema (qualified_fields)

https://github.com/apache/datafusion/blob/f54712d8c2545fc0dd60cdc693704992e9d82eef/datafusion/expr/src/logical_plan/plan.rs#L2953C9-L2977C6

        let group_expr = enumerate_grouping_sets(group_expr)?;

        let is_grouping_set = matches!(group_expr.as_slice(), [Expr::GroupingSet(_)]);

        let grouping_expr: Vec<&Expr> = grouping_set_to_exprlist(group_expr.as_slice())?;

        let mut qualified_fields = exprlist_to_fields(grouping_expr, &input)?;
..
        qualified_fields.extend(exprlist_to_fields(aggr_expr.as_slice(), &input)?);

        let schema = DFSchema::new_with_metadata(
            qualified_fields,
            input.schema().metadata().clone(),
        )?;

        Self::try_new_with_schema(input, group_expr, aggr_expr, Arc::new(schema))
    }

PR adds the same step/logic to correctly retrieve all aggregation expressions when unproject columns. W/o this logic current unproject logic fails as schema does not match agg.group_exp + agg.aggr_expr (must be grouping_set_to_exprlist(agg.group_exp) + agg.aggr_expr) : can't get and then unwrap unprojected expression by index: https://github.com/apache/datafusion/blob/f54712d8c2545fc0dd60cdc693704992e9d82eef/datafusion/sql/src/unparser/utils.rs#L92

Concern

grouping_set_to_exprlist is used directly in find_agg_exp so invoked for each column to unproject (in case of grouping set). This could be optimized to do this only once. Decided to keep this logic this way as pre-calculating and passing such expressions as argument or changing find_agg_exp signature will make code less clean and grouping_set_to_exprlist does NOT create expressions copies (operates by Vec<&Expr>)

[sgrebnov]

Created PR to datafusion combining this and previous improvement. Merged this PR to unblock TPC-DS queries, will add required changes based on review/feedback if any:
apache#12705