dbt-athena does not create "__dbt_tmp" table in a certain condition.

In certain cases, the `__dbt_tmp` table is not created.

Here’s the relevant part of the model configuration:
```python
table_type='iceberg', materialized='incremental', incremental_strategy='merge',
force_batch=True
```

The current logic only creates the __dbt_tmp table when there are records to merge or insert.
If there are no records, the __dbt_tmp table is never created with the config above.
As a result, when the subsequent logic tries to reference this table, the model fails because the expected temporary table doesn’t exist.