'Could not load file or assembly 'System.ComponentModel.Annotations, Version=4.2.0.0' in plugin environment (.NET Framework)

### Describe the bug

Using `ObservableValidator` in a .NET Framework application plugin leads to `System.IO.FileNotFoundException`: Could not load file or assembly 'System.ComponentModel.Annotations, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies.

The referenced System.ComponentModel.Annotations 5.0.0 package brings System.ComponentModel.Annotations 4.6.26515.6 dll.
But CommunityToolkit.Mvvm 8.4.0 dll references System.ComponentModel.Annotations 4.2 dll.

### Regression

_No response_

### Steps to reproduce

Please see attached minimal repro. Build solution and run _AppWithPlugin_.

[AppWithPlugin.zip](https://github.com/user-attachments/files/18905292/AppWithPlugin.zip)

### Expected behavior

System.ComponentModel.Annotations should be resolved.

### Screenshots

_No response_

### IDE and version

VS 2022

### IDE version

17.12.5

### Nuget packages

- [ ] CommunityToolkit.Common
- [ ] CommunityToolkit.Diagnostics
- [ ] CommunityToolkit.HighPerformance
- [x] CommunityToolkit.Mvvm (aka MVVM Toolkit)

### Nuget package version(s)

8.4.0

### Additional context

Why don't you add target framework net472 and reference only the framework provided System.ComponentModel.DataAnnotations and not the annotations nuget package?

### Help us help you

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