Fix mypy errors in sql_to_s3 due to pandas stub bump

[amoghrajesh]

CI fails with:

  providers/amazon/src/airflow/providers/amazon/aws/transfers/sql_to_s3.py:194: error: No overload variant of "__setitem__" of "DataFrame" matches argument types "Hashable", "Series[str]" 
  [call-overload]
                      df[col] = df[col].astype(str)
                      ^~~~~~~
  providers/amazon/src/airflow/providers/amazon/aws/transfers/sql_to_s3.py:194: note: Possible overload variants:
  providers/amazon/src/airflow/providers/amazon/aws/transfers/sql_to_s3.py:194: note:     def __setitem__(self, int | slice[Any, Any, Any] | ndarray[Any, dtype[integer[Any]]] | Index[Any] | list[int] | Series[int] | tuple[int, int] | tuple[slice[Any, Any, Any] | ndarray[Any, dtype[integer[Any]]] | Index[Any] | list[int] | Series[int], int] | tuple[slice[Any, Any, Any] | ndarray[Any, dtype[integer[Any]]] | Index[Any] | list[int] | Series[int], slice[Any, Any, Any] | ndarray[Any, dtype[integer[Any]]] | Index[Any] | list[int] | Series[int]] | tuple[int, slice[Any, Any, Any] | ndarray[Any, dtype[integer[Any]]] | Index[Any] | list[int] | Series[int]], str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any] | IndexOpsMixin[Any, Any] | Sequence[str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any]] | DataFrame | ndarray[tuple[Any, ...], dtype[Any]] | NAType | NaTType | Mapping[Hashable, str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any] | NAType | NaTType] | None, /) -> None
  providers/amazon/src/airflow/providers/amazon/aws/transfers/sql_to_s3.py:194: note:     def [ScalarT: str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any]] __setitem__(self, Series[bool] | ndarray[Any, dtype[bool_]] | list[bool] | str | str_ | <9 more items>, str | bytes | date | datetime | timedelta | <20 more items> | None, /) -> None
  providers/amazon/src/airflow/providers/amazon/aws/transfers/sql_to_s3.py:194: note:     def __setitem__(self, tuple[tuple[IndexOpsMixin[Any, Any] | Series[bool] | ndarray[Any, dtype[bool_]] | list[bool] | str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any] | Sequence[str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any]] | slice[Any, Any, Any], ...], Hashable], str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any] | NAType | NaTType | ExtensionArray | ndarray[Any, dtype[Any]] | IndexOpsMixin[Any, Any] | Sequence[str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any]] | Sequence[Sequence[str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any]]] | Mapping[Hashable, str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any] | NAType | NaTType] | None, /) -> None
  providers/amazon/src/airflow/providers/amazon/aws/transfers/sql_to_s3.py:194: note:     def __setitem__(self, IndexOpsMixin[Any, Any] | DataFrame, str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any] | NAType | NaTType | ExtensionArray | ndarray[Any, dtype[Any]] | IndexOpsMixin[Any, Any] | Sequence[str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any]] | Sequence[Sequence[str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any]]] | Mapping[Hashable, str | bytes | date | datetime | timedelta | <7 more items> | complex | integer[Any] | floating[Any] | complexfloating[Any, Any] | NAType | NaTType] | None, /) -> None
  providers/amazon/src/airflow/providers/amazon/aws/transfers/sql_to_s3.py:204: error: No overload variant of "__setitem__" of "DataFrame" matches argument types "Hashable", "Series[int]" 
  [call-overload]
                          df[col] = df[col].astype(pd.Int64Dtype())

This seems to be due to pandas-stub version bump and this change: pandas-dev/pandas-stubs@3c9e243

To fix this, adding explicit cast() calls to properly handle pandas-stubs 2.3.3 stricter type checking for DataFrame
column assignments. This ensures type safety while maintaining runtime behavior as well.

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[kacpermuda]

I think this fix did not help, still getting the same failures after rebasing: https://github.com/apache/airflow/actions/runs/19857113583/job/56898338352?pr=58933

[potiuk]

I think this fix did not help, still getting the same failures after rebasing: https://github.com/apache/airflow/actions/runs/19857113583/job/56898338352?pr=58933

Fixed in a follow-up