Revert "Use more specific module imports in tests"

This reverts commit 3ce46fe.
The user-facing API (and documentation) is to import the trino package
instead of the specific trino.dbapi module. Integration tests should
test using the import that is documented and part of API.

Author: hashhar

tests/integration/test_dbapi_integration.py

@@ -15,7 +15,7 @@
 import pytest
 import pytz
 
-import trino.dbapi
+import trino
 from trino.exceptions import TrinoQueryError
 from trino.transaction import IsolationLevel