.NET: Add DevUi support for .NET 8

[lukep-infotrack]

It appears that DevUI has a dependency on .NET 9, which I noticed after trying to set it up on a project running .NET 8. The README in the sample project says .NET 8 is supported, however the project itself targets .NET 9. I'd prefer not to migrate to .NET 9 as it doesn't have long term support.

Can support for .NET 8 (or .NET 10) be added so we can make use of DevUI?

csproj file

Sample README

[victordibia]

cc @ReubenBond @DeagleGross

[DeagleGross]

Fixed here #2227