Providing reserved keyword support for `fivetran_utils.add_passthrough_columns()`

Currently, we have trouble bringing through reserved keywords using the `add_passthrough_columns` macro.

This issue was surfaced from an attempt to bring through the `group` field in the `entity` source table in Netsuite2, as it treats group as if it should be used in a group by statement.

Error message:
```
Syntax error: Expected keyword BY but got keyword AS at [373:2]
compiled Code at target/run/netsuite_source/models/netsuite2/stg_netsuite2__entities.sql
```

[See this Height ticket](https://fivetran.height.app/T-710402#activityId=b374dbcb-7f60-4a8c-bcf4-78d4c08dfa9f).