Propagating empty_relation generate an illegal plan

[yukkit]

Describe the bug
A clear and concise description of what the bug is.

When the child node of union contains EmptyRelation, the plan generated by optimization rule propagate_empty_relation is wrong.

To Reproduce
Steps to reproduce the behavior:

1. query

create table m2(intt int) as select 1 as intt;

explain
SELECT 
  *
FROM 
  m2 
WHERE 
  false IS UNKNOWN 
UNION ALL 
SELECT 
  *
FROM 
  m2 
WHERE 
  NOT false IS UNKNOWN 
UNION ALL 
SELECT 
  *
FROM 
  m2 
WHERE 
  false IS UNKNOWN IS NULL;

2. result

+---------------+----------------------------------+
| plan_type     | plan                             |
+---------------+----------------------------------+
| logical_plan  | EmptyRelation                    |
| physical_plan | EmptyExec: produce_one_row=false |
|               |                                  |
+---------------+----------------------------------+

Expected behavior
A clear and concise description of what you expected to happen.

+---------------+-------------------------------------------------+
| plan_type     | plan                                            |
+---------------+-------------------------------------------------+
| logical_plan  | Projection: m2.intt                             |
|               |   TableScan: m2 projection=[intt]               |
| physical_plan | ProjectionExec: expr=[intt@0 as intt]           |
|               |   MemoryExec: partitions=1, partition_sizes=[1] |
|               |                                                 |
+---------------+-------------------------------------------------+

Additional context
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