Add support to upcast numeric types when writing to iceberg tables

[malhotrashivam]

Extension of #5923 on writing side.

This is needed for handling type promotions while writing deephaven tables to iceberg tables.
For example, if Deephaven table has a column of type int whereas iceberg table has same column of type long, we should be able to append this Deephaven table to the iceberg table.
For that, we need to be able to promote types while writing the parquet files.