Application.LoadComponent throws exception when loading XAML resource with AttachedProperty inconsistently

* .NET Core Version: 3.0
* Windows version: 2004
* Does the bug reproduce also in WPF for .NET Framework 4.8?: Inconsistently

**Problem description:**
Loading a XAML resource using Application.LoadComponent will, in some situations, throw an exception when the XAML resource contains an AttachedProperty somewhere inside it.

This is a quick summary of how this issue was found and the attempts made to narrow it's source:

1. The issue was first encountered in a F# WPF application while adding a Interaction.Behaviors (from microsoft/XamlBehaviorsWpf) to a custom Control.

2. Upon inquiry to the aforementioned XamlBehaviorsWpf GitHub [(here)](https://github.com/microsoft/XamlBehaviorsWpf/issues/51), it was determined that this issue was reproducible in C# and reproducible using a simple dummy attached property.

3. While trying to determine whether this issue was reproducible in both .NET Core 3.0 and .NET Framework 4.8, I found that it may be actually something more subtle causing this exception to be thrown, as it would inconsistently occur between F# and C#, between .NET Core 3.0 and .NET Framework 4.8 and between Interaction.Triggers and a dummy AttachedProperty. These attempts are all included in the repro solution, and I tried to make it easy to understand both the attempt and the result. This is a summary:

- C# Project, .NET Core 3.0, Dummy AttachedProperty: **Fails**
- C# Project, .NET Framework 4.8, Dummy AttachedProperty: Passes
- F# Project, .NET Core 3.0, Dummy AttachedProperty: Passes
- F# Project, .NET Framework 4.8, Dummy AttachedProperty: Passes

- C# Project, .NET Core 3.0, Interactions.Triggers: Passes
- C# Project, .NET Framework 4.8, Interactions.Triggers: Passes
- F# Project, .NET Core 3.0, Interactions.Triggers: **Fails**
- F# Project, .NET Framework 4.8, Interactions.Triggers: **Fails**

4. **This is my personal guess, please be aware I have but little understanding of the inner workings of WPF**. I think, as the exception message suggests, that the member created when an AttachedProperty is assigned using DependencyProperty.RegisterAttached in C# is sometimes invisible to Application.LoadComponent, causing the crash. My conclusion is supported by the following:

- All of the dummy AttachedProperties written in F# will not crash, in either .NET Core 3.0 or .NET Framework 4.8.
- A .NET Core 3.0 in C# using the dummy AttachedProperty crashes. (Intriguingly, the .NET 4.8 does not)
- microsoft/XamlBehaviorsWpf is written in C#.

**Actual behavior:**

```
System.Windows.Markup.XamlParseException
HResult=0x80131501
Message='Cannot set unknown member '{clr-namespace:ReproAttachedPropertyCore30.CSharp.Fail}DummyAttached.Foo'.' Line number '11' and line position '6'.
Source=PresentationFramework
StackTrace:
at System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri)
at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, Boolean skipJournaledProperties, Uri baseUri)
at System.Windows.Markup.XamlReader.Load(XamlReader xamlReader, ParserContext parserContext)
at System.Windows.Markup.XamlReader.Load(XmlReader reader, ParserContext parserContext, XamlParseMode parseMode, Boolean useRestrictiveXamlReader, List`1 safeTypes)
at System.Windows.Markup.XamlReader.Load(Stream stream, ParserContext parserContext, Boolean useRestrictiveXamlReader)
at System.Windows.Markup.XamlReader.Load(Stream stream, ParserContext parserContext)
at System.Windows.Application.LoadComponent(Uri resourceLocator, Boolean bSkipJournaledProperties)
at System.Windows.Application.LoadComponent(Uri resourceLocator)
at ReproAttachedPropertyCore30.CSharp.Fail.App.Main(String[] args) in C:\Users\maxim\Downloads\ReproWithBasicProperty\ReproAttachedPropertyCore30.CSharp.Fail\App.cs:line 18

This exception was originally thrown at this call stack:
[External Code]

Inner Exception 1:
XamlObjectWriterException: 'Cannot set unknown member '{clr-namespace:ReproAttachedPropertyCore30.CSharp.Fail}DummyAttached.Foo'.' Line number '11' and line position '6'.
```
**Expected behavior:**
The resource to be loaded correctly, without throwing exceptions.
**Minimal repro:**
[ReproWithBasicProperty.zip](https://github.com/dotnet/wpf/files/5541099/ReproWithBasicProperty.zip)