FixedString is not supported when natively creating iceberg table from clickhouse (related to pr 1896)

[alsugiliazova]

Describe the bug
FixedString should be supported. It supported through PyIceberg, clickhouse maps Iceberg fixed(L) to FixedString(L).

 CREATE TABLE datalake_db_04dd99f0_7b98_11f1_bd2a_de7b9eea3491.`ns_04dd99d2_7b98_11f1_bd2a_de7b9eea3491.t_fixed_04dd9040_7b98_11f1_bd2a_de7b9eea3491` (col FixedString(5))
                         ENGINE = IcebergS3('http://minio:9000/warehouse/data/ns_04dd99d2_7b98_11f1_bd2a_de7b9eea3491/t_fixed_04dd9040_7b98_11f1_bd2a_de7b9eea3491/', 'admin', 'password')
                         SETTINGS write_full_path_in_iceberg_metadata = 1;

Code: 36. DB::Exception: Received from localhost:9000. DB::Exception: Unsupported type for iceberg FixedString(5). (BAD_ARGUMENTS)