Creating a UnitQuaternion from a Rotation3 of NaNs hangs forever

MCVE to reproduce:

```rust
use std::f64::NAN;
use nalgebra::{UnitQuaternion, Rotation3};

fn main() {
let r_br: nalgebra::Matrix3 = nalgebra::Matrix3::new(
NAN, NAN, NAN,
NAN, NAN, NAN,
NAN, NAN, NAN,
);

let q =
UnitQuaternion::from_rotation_matrix(&Rotation3::from_matrix(&r_br)).into_inner();
println!("q: {q}");
}
```