fix `transitive_marker` handling

Without this fix, `test_solver_should_not_raise_errors_for_irrelevant_transitive_python_constraints` wrongly chooses the later `importlib-resources` version even though it is not compatible with the project's python constraint depending on which is resolved first, `virtualenv` or `pre-commit`, because the transitive marker of the other's dependency on `importlib-resources` is ignored.