chore(tox): Fix UV settings for pre-release wheels

Author: effigies

tox.ini

@@ -42,8 +42,9 @@ deps =
   py313: traits @ git+https://github.com/enthought/traits.git@10954eb
 extras = test
 setenv =
-  pre: UV_EXTRA_INDEX_URL=https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
   pre: PIP_EXTRA_INDEX_URL=https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
+  pre: UV_INDEX=https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
+  pre: UV_INDEX_STRATEGY=unsafe-best-match
 uv_resolution =
   min: lowest-direct