fix random item draw (dragoon/komodo!127)

related to
- !122

## description
!122 introduced a `draw_unique_indices` function which uses a `HashSet` to accumulate unique indices in the range `0..<len`.
however, a `HashSet` does not preserve the order of insertion when iterating over the elements of the set... which results in apparent randomness, even though the RNG seed is the same  

this MR switches back to using `shuffle` which used to work, even though a bit less performant    
it's basically a revert of !122, while keeping the refactoring into `random.rs`.

## measuring the performance
i did run the same timing experiment from !122 but with `main` on `bb55005f` and the MR on `fix-shuffle`

| env     | main                   | mr                      | improvement         |
| ------- | ---------------------- | ----------------------- | ------------------- |
| fixed:0 | 6sec 244ms 238µs 45ns | 8sec 734ms 929µs 328ns | -39.88783363238997  |
| fixed:1 | 639ms 720µs 39ns      | 731ms 360µs 261ns      | -14.325051024390373 |

we loose a bit

bins/inbreeding/src/random.rs

-use rand::{Rng, RngCore};
+use rand::{seq::SliceRandom, Rng, RngCore};
 use std::collections::HashSet;
 
+#[allow(dead_code)]
 fn draw_unique_indices(n: usize, vec_len: usize, rng: &mut impl RngCore) -> HashSet<usize> {
     let mut indices = HashSet::new();
 
@@ -17,9 +18,8 @@ pub(super) fn draw_unique_elements<T: Clone>(
     n: usize,
     rng: &mut impl RngCore,
 ) -> Vec<T> {
-    let mut res = vec![];
-    for i in draw_unique_indices(n, things.len(), rng) {
-        res.push(things[i].clone());
-    }
-    res
+    let mut things = things.to_vec();
+    things.shuffle(rng);
+
+    things.iter().take(n).cloned().collect()
 }