Maui FilePicker returns zero files when selecting a lot of files.

### Description

I have implemented the Maui FilePicker.
I am running a MacCatalyst program.
I have no problem selecting one or a few files but if I try to select a lot of files the FilePicker simply returns zero results without any error.

I made a video.
https://www.loom.com/share/acee7f15816949a5b4a1f2abbaa18bf0

### Steps to Reproduce

1. Create a .Net Maui program that targets MacCatalyst.
2. Implement the Maui.File.Picker setting jpeg and png options (as per repo) did not test without this requirement.
3. Select 1000 or more files.

I cannot send the 1000 jpegs so you will need to get those to test, I suppose.

### Link to public reproduction project repository

### Version with bug

7.0 (current)

### Last version that worked well

Unknown/Other

### Affected platforms

macOS, I was *not* able test on other platforms

### Affected platform versions

MacOS 12.5

### Did you find any workaround?

_No response_

### Relevant log output

```shell
Nothing to report - no failures or output
```

Start with the .NET MAUI FilePicker implementation for MacCatalyst and reproduce the issue in a .NET MAUI app by selecting 1,000 or more JPEG or PNG files. Trace why the picker returns zero results without an error, then verify that large multi-file selections return the selected files without regressing smaller selections.

Written by the indexing model from the issue text.