[Android, iOS, Catalyst] TextTransform.Uppercase does not work on Shell SearchHandler

### Description

Setting TextTransform = TextTransform.Uppercase on a SearchHandler attached to a Shell page has no effect. The text entered in the search bar remains in its original casing instead of being transformed to uppercase.

| Other platforms | Windows Output |
|-----------------|---------------|
| | |

### Steps to Reproduce

1. Run the attached sample [IssueSearchHandler 3.zip](https://github.com/user-attachments/files/28388387/IssueSearchHandler.3.zip)
2. In a ContentPage set a SearchHandler on the Shell with TextTransform = TextTransform.Uppercase.
3. Tap the search bar and type text

Expected Behavior
Text typed into the search bar should be displayed in UPPERCASE .

### Link to public reproduction project repository

_No response_

### Version with bug

10.0.70

### Is this a regression from previous behavior?

Not sure, did not test other versions

### Last version that worked well

_No response_

### Affected platforms

Android, iOS, macOS

### Affected platform versions

_No response_

### Did you find any workaround?

_No response_

### Relevant log output

```shell

```

Start by running the attached IssueSearchHandler 3.zip sample and reproducing the behavior on Android, iOS, or macOS, then compare it with the Windows output shown in the issue. Trace the Shell SearchHandler handling of TextTransform.Uppercase; done means text typed into the search bar is displayed in uppercase on the affected platforms.

Written by the indexing model from the issue text.