Fix error in tests with shapely 2.0.5

shapely.Point.coords.xy changed its return type to be consistent with
all other geometry coords.xy return types, but we were relying on the
previous behaviour.

tests/test_plot.py

@@ -48,8 +48,9 @@ def test_add_landmarks():
 
     assert len(landmarks) == len(axes.texts)
     for landmark, text in zip(landmarks, axes.texts):
-        assert text.get_text() == landmark[0]
-        assert text.xy == landmark[1].coords.xy
+        title, point = landmark
+        assert text.get_text() == title
+        assert text.xy == (point.x, point.y)
 
 
 @pytest.mark.mpl_image_compare