Utility to get the table configs in the updated format

Recently changes were made to the [index SPI](https://github.com/apache/pinot/issues/10183). To extract how the current table configs will look in the updated format we need a utility that does this conversion.

For better adaptation of the updated format let's
- have a utility method which accepts the table config in older format and return the table config in updated format.
- introduce a flag as a query parameter for `/tableConfigs/{tableName}`, which when passed returns the existing table config in updated format.

Start with the index SPI changes described in issue #10183 and trace the /tableConfigs/{tableName} endpoint. Identify where older table configs are handled and define the conversion entry point. Done means the utility returns the updated format and the query flag makes the endpoint return that format.

Written by the indexing model from the issue text.