Dependabot on steroids: Update DefaultVersions.props

https://github.com/dotnet/arcade/blob/d83761aff116d58009415d85889625c4d38d809e/src/Microsoft.DotNet.Arcade.Sdk/tools/DefaultVersions.props

It would be good to update the versions in DefaultVersions.props as many of those are stale or manually updated, i.e. https://github.com/dotnet/arcade/pull/16985.

We already have dependabot enabled in this repository for in-repo dependencies. That infrastructure isn't able to handle these sdk provided properties though. An agentic workflow that mimics dependabot could be set-up to keep those up-to-date.