MAUI App that uses existing MVVMCross ViewModels - Fails with mismatch in Dependencies for Android as Target
## 🐛 Bug Report

I have an existing WPF application where the view models are borrowed from a Plugin Architecture. The ViewModels are all derived from MvxViewModel. This is a dependency that cannot be easily removed. 

On creating a vanilla MAUI Application using Visual Studio 2022 (Version 17.7.6), there is a conflict in the dependencies of MAUI project and the plugin central framework that uses MVVMCross and MVVMCross.Plugin.Messenger. 

To isolate the problem, I have created a simple Visual Studio solution [here](https://github.com/revred/MAUI.Cross).

The conflict is related to the mismatch in versions of a deeper dependency which results in a message that is shown below

```
2>D:\code\TestMaui\MAUI.Cross\MAUI.Cross\MAUI.Cross.csproj : error NU1605: Warning As Error: Detected package downgrade: Xamarin.Google.Android.Material from 1.9.0.2 to 1.7.0. Reference the package directly from the project to select a different version. 
2>D:\code\TestMaui\MAUI.Cross\MAUI.Cross\MAUI.Cross.csproj : error NU1605:  MAUI.Cross -> MVCX.Model -> MvvmCross 9.1.1 -> Xamarin.Google.Android.Material (>= 1.9.0.2) 
2>D:\code\TestMaui\MAUI.Cross\MAUI.Cross\MAUI.Cross.csproj : error NU1605:  MAUI.Cross -> Xamarin.Google.Android.Material (>= 1.7.0)
2>D:\code\TestMaui\MAUI.Cross\MAUI.Cross\MAUI.Cross.csproj : error NU1605: Warning As Error: Detected package downgrade: Microsoft.WindowsAppSDK from 1.3.230724000 to 1.2.221209.1. Reference the package directly from the project to select a different version. 
2>D:\code\TestMaui\MAUI.Cross\MAUI.Cross\MAUI.Cross.csproj : error NU1605:  MAUI.Cross -> MVCX.Model -> MvvmCross 9.1.1 -> Microsoft.WindowsAppSDK (>= 1.3.230724000) 
2>D:\code\TestMaui\MAUI.Cross\MAUI.Cross\MAUI.Cross.csproj : error NU1605:  MAUI.Cross -> Microsoft.WindowsAppSDK (>= 1.2.221209.1)
2>Done building project "MAUI.Cross.csproj" -- FAILED.
```
I have tried upgrading/downgrading MAUI Nuget Package but this was not resolved. I have also tried to check if I can change the framework to use a specific version of Xamarin.Google.Android.Material but there is no option to do this.

If I remove the .NET7 android target framework, then the application builds with no issues.

### Expected behavior

I would expect the MAUI application with target as android to work with MVVMCross view models just like it behaves with Mac or Windows.

### Reproduction steps

Create a .NET MAUI App in Visual Studio
Create a viewModel in a separate C# dotNET library that is derived from MvxViewModel. Install the nuget packages of MVVMCross and MVVMCross.Plugin.Messenger in that C# library. 
Use this viewModel for a page that is rendered in MAUI. 

Build and check the errors.

### Configuration
MVVMCross Version 9.0.*
MVVMCross.Plugin.Messenger Version 9.0.*

### Platform

Application created on a windows machine with target as android.
Visual Studio 2022 - Version 17.7.6