Fix table changes test

Author: OussamaSaoudi

kernel/src/table_changes/mod.rs

@@ -302,7 +302,7 @@ mod tests {
         let path = "./tests/data/table-with-cdf";
         let engine = Box::new(SyncEngine::new());
         let table = Table::try_from_uri(path).unwrap();
-        let expected_msg = "Failed to build TableChanges: Generic delta kernel error: Read field is non-nullable while this field is nullable\n Found start version schema StructType { type_name: \"struct\", fields: {\"part\": StructField { name: \"part\", data_type: Primitive(Integer), nullable: true, metadata: {} }, \"id\": StructField { name: \"id\", data_type: Primitive(Integer), nullable: true, metadata: {} }} } and end version schema StructType { type_name: \"struct\", fields: {\"part\": StructField { name: \"part\", data_type: Primitive(Integer), nullable: true, metadata: {} }, \"id\": StructField { name: \"id\", data_type: Primitive(Integer), nullable: false, metadata: {} }} }";
+        let expected_msg = "Failed to build TableChanges: The nullability was tightened for a field\n Found start version schema StructType { type_name: \"struct\", fields: {\"part\": StructField { name: \"part\", data_type: Primitive(Integer), nullable: true, metadata: {} }, \"id\": StructField { name: \"id\", data_type: Primitive(Integer), nullable: true, metadata: {} }} } and end version schema StructType { type_name: \"struct\", fields: {\"part\": StructField { name: \"part\", data_type: Primitive(Integer), nullable: true, metadata: {} }, \"id\": StructField { name: \"id\", data_type: Primitive(Integer), nullable: false, metadata: {} }} }";
 
         // A field in the schema goes from being nullable to non-nullable
         let table_changes_res = table.table_changes(engine.as_ref(), 3, 4);