Add MS Graph SDK v5 guidance

[guardrex]

Addresses #28001
Fixes #28573

Thanks @cloudhal! 🚀 ... I'm still working on this. It's just a draft at the moment, while I work on a service registration problem with the custom account factory approach. I'll call for one of the product unit engineers to help if I can't figure it out.

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Internal previews

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aspnetcore/blazor/security/webassembly/graph-api.md	aspnetcore/blazor/security/webassembly/graph-api

[guardrex]

Ok ... I think I figured it out 🎉. I should be able to wrap this up. I DO want to get the service registration reviewed. The service registration is a bit tricky this time around, just because the parameters must be passed to the Graph client when it's instantiated or else it 💥 up with a cryptic error about not being able to create an IRequestAdapter service for the Graph client.

... and I'm making an additional change to the whole topic. I don't think that splitting out the Graph client version makes sense. I'm rolling that back into the base URL out of configuration now.

UPDATE: I sent an email to Mackinnon to ask if he has any concerns about my factory service activation. It ✨ Just Works!™ ✨, so at least it has that going for it 😄. I'm going to perform a final review and update on this and hear back from him before merging. @cloudhal, if you have time to look this over, feedback is welcome. If not tho, no worries. Most of the updates here are of the general improvement variety.