Fix support for native AOT in minimal (#42272)

* Fix support for native AOT in minimal
- This includes 2 major changes to fix native AOT support in .NET 7. Explicitly rooting the indexers of various binding sources (query, formfile, header, routes). NativeAOT seems a bit more aggressive here.
- We avoid the filter optimization that uses generics to avoid boxing. NativeAOT needs to see generic instantiations statically which we cannot do here.