Port Ignore NotImplementedException from ITaskbarList to Dotnet 6.0.20

We are using Dotnet 6.0.15/20 runtime for our WPF application. And saw an issue with taskbarlist throwing not implemented exception.

Looks like this was fixed as part of the commit https://github.com/dotnet/wpf/commit/c308dfcad75d7b491ea88d39118fb8aee70d6b87

This commit or fix is not available in 6.0.15/20 version but is present in 8.0 preview versions. (https://github.com/dotnet/wpf/blob/v8.0.0-preview.6.23329.2/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Window.cs#L640)

This request is to port this commit to earlier version 6.0.20?