[SPARK-42831][SQL] Show result expressions in AggregateExec

[wankunde]

What changes were proposed in this pull request?

If the result expressions in AggregateExec are not empty, we should display them. Or we will get confused because some important expressions do not show up in the DAG.

Why are the changes needed?

For example, the plan for query SELECT sum(p) from values(cast(23.4 as decimal(7,2))) t(p) was incorrect because the result expression MakeDecimal(sum(UnscaledValue(p#0))#1L,17,2) AS sum(p)#2 is not displayed

Before

== Physical Plan ==
AdaptiveSparkPlan isFinalPlan=false
+- HashAggregate(keys=[], functions=[sum(UnscaledValue(p#0))], output=[sum(p)#2])
   +- Exchange SinglePartition, ENSURE_REQUIREMENTS, [plan_id=11]
      +- HashAggregate(keys=[], functions=[partial_sum(UnscaledValue(p#0))], output=[sum#5L])
         +- LocalTableScan [p#0]

After

== Physical Plan ==     
AdaptiveSparkPlan isFinalPlan=false
+- HashAggregate(keys=[], functions=[sum(UnscaledValue(p#0))], results=[MakeDecimal(sum(UnscaledValue(p#0))#1L,17,2) AS sum(p)#2], output=[sum(p)#2])
   +- Exchange SinglePartition, ENSURE_REQUIREMENTS, [plan_id=38]
      +- HashAggregate(keys=[], functions=[partial_sum(UnscaledValue(p#0))], results=[sum#13L], output=[sum#13L])
         +- LocalTableScan [p#0]

Does this PR introduce any user-facing change?

No

How was this patch tested?

Local test

[github-actions]

We're closing this PR because it hasn't been updated in a while. This isn't a judgement on the merit of the PR in any way. It's just a way of keeping the PR queue manageable.
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