Install the test dep group for codspeed

Author: Tinche

.github/workflows/codspeed.yml

@@ -39,4 +39,4 @@ jobs:
         uses: CodSpeedHQ/action@346a2d8a8d9d38909abd0bc3d23f773110f076ad  # v4.4.1
         with:
           mode: simulation
-          run: uv run --with pytest-codspeed --with pytest-benchmark pytest --codspeed bench/
+          run: uv run --with pytest-codspeed --with pytest-benchmark --group test pytest --codspeed bench/