value error: probabilities are less than 0

[theoden8]

https://github.com/explodinggradients/ragas/blob/main/src/ragas/testset/docstore.py#L325 there's a bug here

It can be patched by either, setting prob[prob < 0] = .0 before normalization or by adding prob += eps. Here are the min and max values I have:

> prob.min(), prob.max(), prob.sum()
(-2.47917840909896e-05, 0.0005422972470319377, 1.0)