tests: tweak `test_pip_wheel_with_user_set_in_config` (#5428)
tests: tweak `test_pip_wheel_with_user_set_in_config` (#5428)

To reduce failures when connection to PyPI is [flaky](https://ci.appveyor.com/project/benoit-pierre/pip/build/1.0.293/job/qohehq43vuwiek1p#L164).

pfmoore/pip,xavfernandez/pip,xavfernandez/pip,rouge8/pip,techtonik/pip,pfmoore/pip,rouge8/pip,pypa/pip,techtonik/pip,RonnyPfannschmidt/pip,RonnyPfannschmidt/pip,pradyunsg/pip,techtonik/pip,RonnyPfannschmidt/pip,xavfernandez/pip,rouge8/pip,sbidoul/pip,sbidoul/pip,pypa/pip,pradyunsg/pip