fix: Force Db2 FOR BIT DATA columns to Ibis Binary

[nj1973]

Description of changes

This PR ensure Db2 FOR BIT DATA data types are detected as Ibis Binary columns and not strings.

FOR BIT DATA columns are not obviously marked as such in the Db2 data dictionary, we need to reference the CODEPAGE column in the raw data types.

This PR also changes the integration test to use a more realistic data value for the FOR BIT DATA columns - a UUID.

TODO: After merging the work we need to make the DDL/DML changes to the BigQuery test table in order for tests to pass. I've been temporarily making the changes, running tests and then reverting them while working on this fix.

Issues to be closed

Closes #1655

Checklist

• I have followed the CONTRIBUTING Guide.
• I have commented my code, particularly in hard-to-understand areas
• I have updated any relevant documentation to reflect my changes, if applicable
• I have added unit and/or integration tests relevant to my change as needed
• I have already checked locally that all unit tests and linting are passing (use the tests/local_check.sh script)
• I have manually executed end-to-end testing (E2E) with the affected databases/engines

[nj1973]

/gcbrun