feat: copy option 'pattern' support variable.

[youngsofun]

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Summary

select $1 from @data/csv/ (pattern => $pt, file_format=>'csv')
copy into t1 from @data/csv/ pattern= $pt file_format=(type=csv)

Tests

• Unit Test
• Logic Test
• Benchmark Test
• No Test - Explain why

Type of change

• 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