Add missing `type` field for the `Int32` data type

[deepyaman]

Just noticed this bug as I was working on type tests, just in case anybody runs into issue with it

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 92.77%. Comparing base (4df61da) to head (2256c83). Report is 148 commits behind head on ibis-dev.

Additional details and impacted files

@@             Coverage Diff              @@
##           ibis-dev    #1771      +/-   ##
============================================
- Coverage     94.29%   92.77%   -1.52%     
============================================
  Files            91      130      +39     
  Lines          7024     9451    +2427     
============================================
+ Hits           6623     8768    +2145     
- Misses          401      683     +282     

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[cosmicBboy]

error seems unrelated to this PR:

    @classmethod
    def infer_column(cls, column: Sequence) -> dt.DataType:
        """Infer the ibis type of a sequence."""
        import pyarrow as pa
>       import pyarrow_hotfix  # noqa: F401
E       ModuleNotFoundError: No module named 'pyarrow_hotfix'