fix: aggregation empty row on join with grouping and aggregations

[harshit-gangal]

Description

This PR fixes an aggregation-grouping bug in gen4 that does non-scalar aggregates on a top of a join.
This happens when the left side of the join has data and no data is present on the right hand side.
If the right hand side of the join only contains an aggregation then even though the table has no data it will return count(*) as 0 and that will get mapped to the join output.
To avoid such scenario the change adds a grouping condition on the right hand side using literal 1 so that the rows from right hand side is only returned when the join condition matches.

Related Issue(s)

Checklist

• "Backport me!" label has been added if this change should be backported 14.0
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• Documentation was added or is not required

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