Editor.AutoSize="TextChanges" Does Not Update Placeholder on iOS and MacCatalyst

### Description

When using Editor.AutoSize="TextChanges", the Editor is expected to resize dynamically based on the text content. However, on iOS and MacCatalyst, while the Editor content may update, the placeholder layout does not update correctly during resizing.

### Output Screenshot
On Android | On IOS |
|----------|----------|
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### Steps to Reproduce

- Create an Editor with both Placeholder and AutoSize="TextChanges". [EditorControl.zip](https://github.com/user-attachments/files/21180674/EditorControl.zip)

- Run the app on iOS or Mac.
- Add and delete text to trigger auto-resizing.
- Observe that the placeholder does not adjust or align correctly.

**Expected Behavior:** The placeholder should remain properly aligned and visible as the Editor resizes dynamically.

**Actual Behavior:** The placeholder does not reposition or resize in sync with the Editor. The placeholder appears misaligned or clipped when text is added or removed.

### Link to public reproduction project repository

_No response_

### Version with bug

10.0.0-preview.1

### Is this a regression from previous behavior?

Not sure, did not test other versions

### Last version that worked well

Unknown/Other

### Affected platforms

iOS, macOS

### Affected platform versions

_No response_

### Did you find any workaround?

_No response_

### Relevant log output

```shell

```

Start with the attached EditorControl.zip reproduction and run it on iOS and MacCatalyst using Editor.AutoSize="TextChanges" with a placeholder. Observe placeholder positioning while adding and deleting text; done means the placeholder remains aligned and visible as the editor resizes dynamically on both affected platforms.

Written by the indexing model from the issue text.