bug(cdkDrag): Issue scrolling/reordering "reversed" lists

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

For design/UX reasons, I'm using `cdk/drag-drop` on a list with `flex-direction: row-reverse` applied. Scrolling does not trigger while dragging among other issues.

Can we get a "reversed" option to support this use case?

### Reproduction

Steps to reproduce:`
1. Apply `display: flex; flex-direction: row-reverse;` to a `cdkDropList`
2. Try to drag+scroll an element

### Expected Behavior

It would be nice if indexes and scroll behavior could work intuitively by adding a `reversed` option

### Actual Behavior

The drag will not scroll the `cdkDropList`

### Environment

- Angular: v19.0.0
- CDK/Material: v19.0.0
- Browser(s): All
- Operating System: Ubuntu

Comienza con el comportamiento de arrastrar y soltar de cdkDropList usando la reproducción indicada: aplica flex-direction: row-reverse y arrastra un elemento mientras haces scroll. Traza cómo se comportan los índices y el desplazamiento en la lista invertida y, después, verifica que el desplazamiento funciona y que el orden sigue siendo intuitivo en la reproducción de Angular 19.

Escrito por el modelo de indexación a partir del texto del issue.