[iOS] Vertical `SafeAreEdge` isn't respected when `Top` and `Bottom` constraints mismatch

### Description

I want my page to be displayed behind the status bar (top safe area), but not behind the bottom safe area.
To do so, I set `SafeAreaEdges="None,None,None,Container"` at the page level.

I also want some sub elements to avoid the safe areas.
To do so, I set `SafeAreaEdges="Container"` at the element level.

This works pretty well on Android for all cases.

https://github.com/user-attachments/assets/dbc7c2d4-f473-45be-817f-77c474b06a31

This works well on iOS when the top and bottom container `SafeAreaRegion` matches, but not when they differ.
The sub elements might be displayed in the safe area

https://github.com/user-attachments/assets/0cbf4a1e-fe44-4a4b-88b3-306a5e0395a0

I've tested the following versions:

| Version | Status |
|--------|--------|
| `10.0.1` | ✅ |
| `10.0.50` | ❌ |
| `10.0.60-ci.main.26168.7` | ❌ |

### Steps to Reproduce

1. Clone the reproduction project repo
2. Run the app

### Link to public reproduction project repository

https://github.com/EmilienDup/MAUISafeAreaEdgesMismatchingVerticalConstraintiOSBug

### Version with bug

10.0.50

### Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

### Last version that worked well

10.0.1

### Affected platforms

iOS

### Affected platform versions

_No response_

### Did you find any workaround?

_No response_

### Relevant log output

```shell

```

Start with the linked reproduction project and run it on iOS using .NET MAUI 10.0.50, then compare it with 10.0.1. Trace the iOS handling of the page and element SafeAreaEdges values when the top and bottom constraints differ. Done means the reproduction keeps sub-elements out of the intended safe areas in the mismatched-constraint case, with regression coverage for that behavior.

Written by the indexing model from the issue text.