fix(query): fix distinct set-returning function

[b41sh]

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Summary

fix distinct set-returning function

for example

root@0.0.0.0:48000/default> select distinct unnest(split(coalesce(NULL, 'a,b,a,b,c'), ',')) as c1;
┌──────────────────┐
│        c1        │
│ Nullable(String) │
├──────────────────┤
│ a                │
│ b                │
│ c                │
└──────────────────┘
3 rows read in 0.117 sec. Processed 1 rows, 1 B (8.55 rows/s, 8 B/s)

• fixes: #16873

Tests

• [ ] Unit Test
• [x] Logic Test
• [ ] Benchmark Test
• [ ] No Test - Explain why

Type of change

• [x] Bug Fix (non-breaking change which fixes an issue)
• [ ] New Feature (non-breaking change which adds functionality)
• [ ] Breaking Change (fix or feature that could cause existing functionality not to work as expected)
• [ ] Documentation Update
• [ ] Refactoring
• [ ] Performance Improvement
• [ ] Other (please describe):

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This change is