Fix mismatched scope async tests.

Author: ayjayt

src/py/tests/test_kaleido.py

@@ -10,17 +10,21 @@
 
 
 @pytest.fixture(scope="session")
-async def simple_figure_with_bytes():
+def simple_figure_with_bytes():
     """Create a simple figure with calculated bytes and PNG assertion."""
     import plotly.express as px  # noqa: PLC0415
 
     fig = px.line(x=[1, 2, 3], y=[1, 2, 3])
 
-    async with Kaleido() as k:
-        bytes_data = await k.calc_fig(
-            fig,
-            opts={"format": "png", "width": 400, "height": 300},
-        )
+    async def build_obj():
+        async with Kaleido() as k:
+            bytes_data = await k.calc_fig(
+                fig,
+                opts={"format": "png", "width": 400, "height": 300},
+            )
+        return bytes_data
+
+    bytes_data = asyncio.run(build_obj())
 
     # Assert it's a PNG by checking the PNG signature
     assert bytes_data[:8] == b"\x89PNG\r\n\x1a\n", "Generated data is not a valid PNG"