Bug Report: Column Nullability Not Honored in FlightSqlProducer Schema

### Describe the bug, including details regarding any error messages, version, and platform.

In the FlightSqlProducer class, the getFlightInfoPreparedStatement method is responsible for returning the Arrow Schema of the ResultSet for a given query. However, the returned schema does not accurately reflect the nullability of columns. Regardless of whether a column is defined as nullable or non-nullable, the schema always returns a fixed nullability value.

This leads to incorrect ResultSetMetaData when the schema is consumed via the Flight SQL driver.

Root Cause:

The issue originates in the method:

`org.apache.arrow.driver.jdbc.utils.ConvertUtils.convertArrowFieldsToColumnMetaDataList()`

Here, a list of `org.apache.arrow.vector.types.pojo.Field` objects is converted into `org.apache.calcite.avatica.ColumnMetaData` instances. However, the `setNullable` property of the `ColumnMetaData.Builder` is not being set based on the actual nullability of the Arrow field.

Expected Behavior:

The `setNullable` method of `ColumnMetaData.Builder` should be updated to reflect the value of `field.isNullable()` from the Arrow schema.

Impact:

This bug results in incorrect metadata being exposed to clients using the Flight SQL driver, potentially leading to misinterpretation of the data schema.

Commencez par org.apache.arrow.driver.jdbc.utils.ConvertUtils.convertArrowFieldsToColumnMetaDataList(), qui convertit les objets Arrow Field en instances de ColumnMetaData pour le pilote Flight SQL. Vérifiez comment ColumnMetaData.Builder est renseigné et assurez-vous que les métadonnées obtenues préservent la nullabilité de chaque champ. La tâche est terminée lorsque les champs Arrow nullable et non-nullable exposent des valeurs ResultSetMetaData correspondantes.

Rédigé par le modèle d'indexation à partir du texte de l'issue.