## Proposed changes
Fix type check of ubsan.
```
/root/doris/be/src/vec/exec/format/parquet/fix_length_plain_decoder.h:75:78: runtime error: member call on address 0x5582f35db5c0 which does not point to an object of type 'doris::vectorized::ColumnVector<signed char>'
0x5582f35db5c0: note: object is of type 'doris::vectorized::ColumnVector<int>'
83 55 00 00 78 c0 b0 5a 82 55 00 00 02 00 00 00 00 00 00 00 10 a0 00 d7 83 55 00 00 10 a0 00 d7
^~~~~~~~~~~~~~~~~~~~~~~
vptr for 'doris::vectorized::ColumnVector<int>'
doris::Status doris::vectorized::FixLengthPlainDecoder::_decode_values<false>(COW<doris::vectorized::IColumn>::mutable_ptr<doris::vectorized::IColumn>&, std::shared_ptr<doris::vectorized::IDataType const>&, doris::vectorized::ColumnSelectVector&, bool) at fix_length_plain_decoder.h:75:78
```
e4b6dac0c1