Param `mean` in Random.multivariateNormal doesn't need to be a KtNDArray

It is 1-D array_like thing and can be just a std Kotiln collection.

Instead of
```
Random.multivariateNormal(mean=array(listOf(-2,0)), ...
```

would be nice to have:
```
Random.multivariateNormal(mean=listOf(-2,0), ...
```

Start at the Random.multivariateNormal entry point and inspect how the mean parameter is typed and passed to the NumPy binding. Update the API so the requested Kotlin collection form is supported, then verify the existing multivariateNormal examples or tests cover both forms.

Written by the indexing model from the issue text.