Add query_id assertions to async polars cursor tests

Add assertions to verify query_id is not None in tests where the
variable was previously unused, improving test coverage.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: laughingman7743

tests/pyathena/polars/test_async_cursor.py

@@ -222,6 +222,7 @@ def test_bad_query(self, async_polars_cursor):
     )
     def test_as_polars(self, async_polars_cursor):
         query_id, future = async_polars_cursor.execute("SELECT * FROM one_row")
+        assert query_id is not None
         df = future.result().as_polars()
         assert isinstance(df, pl.DataFrame)
         assert df.height == 1
@@ -235,6 +236,7 @@ def test_as_polars(self, async_polars_cursor):
     )
     def test_many_as_polars(self, async_polars_cursor):
         query_id, future = async_polars_cursor.execute("SELECT * FROM many_rows")
+        assert query_id is not None
         df = future.result().as_polars()
         assert isinstance(df, pl.DataFrame)
         assert df.height == 10000
@@ -247,6 +249,7 @@ def test_many_as_polars(self, async_polars_cursor):
     )
     def test_as_arrow(self, async_polars_cursor):
         query_id, future = async_polars_cursor.execute("SELECT * FROM one_row")
+        assert query_id is not None
         table = future.result().as_arrow()
         assert table.num_rows == 1
         assert table.num_columns == 1
@@ -297,6 +300,7 @@ def test_empty_result(self, async_polars_cursor):
             LOCATION '{ENV.s3_staging_dir}{ENV.schema}/{table}/'
             """
         )
+        assert query_id is not None
         df = future.result().as_polars()
         assert df.height == 0
         assert df.width == 0
@@ -316,6 +320,7 @@ def test_empty_result_unload(self, async_polars_cursor):
             SELECT * FROM one_row LIMIT 0
             """
         )
+        assert query_id is not None
         df = future.result().as_polars()
         assert df.height == 0
         assert df.width == 0