SVD::solve quietly produces invalid solution for certain matrices

Example ([playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=2014f0f649d78eb052d58e422ecaf93e)):

```rust
let matrix = nalgebra::matrix![
1., 0., 2.;
3., 0., 4.;
5., 0., 6.
];

let svd = matrix.svd(true, true);
let solution = svd.solve(&matrix, 0.0).unwrap();

println!("solution for self: {:.3}", solution);
/*
Output:

solution for self:
┌ ┐
│ 1.000 0.000 -0.000 │
│ 18014398509481988.000 0.000 18014398509481988.000 │
│ 4.000 0.000 5.000 │
└ ┘
*/

println!("apply solution: {:.3}", matrix * solution);
/*
Output:

apply solution:
┌ ┐
│ 9.000 0.000 10.000 │
│ 19.000 0.000 20.000 │
│ 29.000 0.000 30.000 │
└ ┘
*/
```

I'm not deeply familiar with matrix decompositions, so I don't know if this is a fundamental limitation of SVD and whether it's possible to fix it to produce a correct result in this case, but at least I would expect the `.solve()` to return an error in this case instead of quietly returning invalid solution.