bug(MatTree): padding is not recomputed when moving a node inside/outside an expandable node

### 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

As `TreeControl` is deprecated, I started migrating to the latest API using `childrenAccessor`. So far so good, except for one case not working any more.

I'm using `matTreeNodePadding` and `matTreeNodePaddingIndent` on ``. When I move a node inside/outside of an expandable node, padding is not recomputed as-is.

Expanding/collapsing the parent node in which the node was moved, will recompute its padding though.

### Reproduction

Minimal example on [Stackblitz](https://stackblitz.com/~/github.com/poirierlouis/ng-issue-29959).

Steps to reproduce:
1. Open link
2. Open preview in a new tab
3. Open both folders (`/` and `home`)
4. Follow instructions to move a node outside its parent node

`dataSource` is updated with a new array, using the same items. Can it be a source of error? Should the entire tree be cloned somehow, to trigger changes detection down to padding computation?

### Expected Behavior

When a node is moved inside/outside of an expandable node (level is changed), padding should be recomputed based on the new level of the node.

### Actual Behavior

Padding of the node is not updated when moving the node inside/outside of an expandable node.

### Environment

- Angular: 18.2.10
- CDK/Material: 18.2.11
- Browser(s): Firefox / Chrome
- Operating System (e.g. Windows, macOS, Ubuntu): Windows

Start with the linked StackBlitz reproduction and inspect the matTreeNodePadding behavior when using childrenAccessor and moving a node between expandable parents. Trace how the node level changes and how padding is recomputed, then verify that moving the node updates its padding without expanding or collapsing the parent.

Written by the indexing model from the issue text.