Consider refactoring ScopeExtensions

We have some [ScopeExtensions for ASP.NET Core]() that get \[trigged by the SentryMiddleware\]([https://github.com/getsentry/sentry-dotnet/blob/d1e5efcdf3af763ad49f11cd2426cc14a315a901/src/Sentry.AspNetCore/SentryMiddleware.cs#L258]().

In classic [ASP.NET]() apps, something similar (but not identical) happens in the [SystemWebRequestEventProcessor]().

Ideally both platforms would share some common logic so that fixes we applied to one would get applied to the other. Would need a bit of head scratching to come up with a way to do this since they pull their information from different contexts (and have different scope stack containers).

*Originally posted by @jamescrosswell in *[*#3337*]()