Chore: attempt to fix flakey dbt test

[georgesittas]

Simple approach attempting to fix the following issue observed in CI/CD:

ERROR tests/dbt/test_model.py::test_load_multiple_snapshots_defined_in_same_file - sqlmesh.utils.errors.SQLMeshError: Failed to load dbt manifest: Compilation Error in model waiter_revenue_by_day (models/waiter_revenue_by_day.sql)
  In dispatch: No macro named 'current_engine' found within namespace: 'customers'
      Searched for: 'duckdb__current_engine', 'default__current_engine'

[georgesittas]

Closing because Chris is already looking into this and there may be an underlying issue with dbt's loader & the cache.