[Bug] Snapshot custom colum names

[danielefrigo]

Is this a new bug?

• I believe this is a new bug
• I have searched the existing issues, and I could not find an existing issue for this bug

Which packages are affected?

• dbt-adapters
• dbt-tests-adapter
• dbt-athena
• dbt-athena-community

Current Behavior

The new snapshot config snapshot_meta_column_names works fine with lower case column names.
If I configure a snapshot with upper case custom column names, the first run works fine and generates the table as expected, while the second brakes with the error:

Snapshot target is missing configured columns (missing "SCD_HK", "START_TS", "END_TS")

I believe the error is here: target relation column are put lowercase, while the config ones are retained in their original case, generating the error.

Expected Behavior

The new snapshot config snapshot_meta_column_names should work with both lower and upper case column names.

Steps To Reproduce

1. create a new snapshot
2. add snapshot_meta_column_names = {'dbt_scd_id': "SCD_HK"}
3. run the snapshot twice

Relevant log output

Environment

- OS: Windows 11
- Python: 3.12
- dbt-adapters: 1.9.0
- dbt-bigquery: 1.9.1

Additional Context

No response