fix a dcheck error for vertical compaction on Merge-On-Write table。
When merge rowsets with empty segment, VerticalHeapMergeIterator::init
return ok directly and _record_rowids not set, dcheck failed when
_unique_key_next_block call current_block_row_locations。
1. remove FE config `enable_array_type`
2. limit the nested depth of array in FE side.
3. Fix bug that when loading array from parquet, the decimal type is treated as bigint
4. Fix loading array from csv(vec-engine), handle null and "null"
5. Change the csv array loading behavior, if the array string format is invalid in csv, it will be converted to null.
6. Remove `check_array_format()`, because it's logic is wrong and meaningless
7. Add stream load csv test cases and more parquet broker load tests
