[Refactor] refactor complex_column_reader on variant type

[dirtysalt]

Why I'm doing:

What I'm doing:

Fixes #issue

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• Interface/UI changes: syntax, type conversion, expression evaluation, display information
• Parameter changes: default values, similar parameters but with different default values
• Policy changes: use new policy to replace old one, functionality automatically enabled
• Feature removed
• Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• I have added test cases for my bug fix or my new feature
• This pr needs user documentation (for new or modified features or behaviors)
  • I have added documentation for my new feature or new function
  • This pr needs auto generate documentation
• This is a backport pr

Bugfix cherry-pick branch check:

• I have checked the version labels which the pr will be auto-backported to the target branch
  • 4.1
  • 4.0
  • 3.5
  • 3.4

[CelerData-Reviewer]

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[chatgpt-codex-connector]

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[github-actions]

[Java-Extensions Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[FE Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[BE Incremental Coverage Report]

❌ fail : 164 / 248 (66.13%)

file detail

	path	covered_line	new_line	coverage	not_covered_line_detail
🔵	be/src/formats/parquet/complex_column_reader.cpp	150	231	64.94%	[815, 823, 824, 826, 896, 897, 898, 951, 952, 991, 994, 995, 1005, 1006, 1024, 1025, 1043, 1053, 1062, 1063, 1078, 1089, 1090, 1114, 1269, 1283, 1284, 1285, 1290, 1291, 1293, 1310, 1311, 1313, 1362, 1363, 1377, 1391, 1392, 1399, 1402, 1403, 1404, 1405, 1406, 1408, 1409, 1414, 1415, 1420, 1421, 1424, 1486, 1512, 1535, 1536, 1537, 1539, 1540, 1541, 1543, 1587, 1593, 1603, 1640, 1641, 1642, 1644, 1647, 1648, 1649, 1651, 1652, 1653, 1654, 1655, 1656, 1657, 1658, 1668, 1670]
🔵	be/src/formats/parquet/column_reader_factory.cpp	9	12	75.00%	[504, 505, 506]
🔵	be/src/formats/parquet/complex_column_reader.h	5	5	100.00%	[]