Issue on docs: Incorrect Configuration Variable in Iceberg Docs

[Ad-Bean]

(A-creating-and-using-a-table)[https://docs.risingwave.com/iceberg/managed/hosted-iceberg-catalog#example%3A-creating-and-using-a-table]

-- Step 2: Set the connection as the default for the Iceberg engine
SET rw_iceberg_connection = 'iceberg_catalog';

The rw_iceberg_connection should be iceberg_engine_connection like risingwave e2e test:

set iceberg_engine_connection = 'public.iceberg_catalog';