JDBC Catalog create table DDL is not compatible for MYSQL 8.0.29

[noneback]

env: Ubuntu 20.04LTS, MYSQL 8.0.29 with InnoDB, Iceberg-flink-runtime built from the main branch, Flink1.15.

I am trying to use JDBC as the catalog in flink with iceberg, and I cannot create those iceberg_namespace_properties table because the attributes are too long as an index key.

The index key prefix length limit is 3072 bytes but in iceberg_namespace_properties, the index is longer than 5500.

Ref: #5014

MySQL 8.0 Reference Manual

[Kontinuation]

NAMESPACE_PROPERTY_KEY was defined as VARCHAR(5500), it may not have to be that long. Some value less than 500 is good enough I guess?

[nastra]

@noneback are you able to increase the limit on MySql? Usually different databases impose different limits, but I'll see if we can lower namespace properties from 5500.

[nastra]

I have created to https://github.com/apache/iceberg/pull/6338 to make this less of an issue with MySql