Analyzers should be able to detect that a call is intercepted

[RikkiGibson]

Related to #67421

We think that eventually a public API is going to be needed for analyzers to tell if a call is being intercepted. However, we currently don't know how such an API should work, and we're also not certain of how it would need to be implemented in order to have acceptable perf characteristics in the IDE.

This is something we'll want to address post-.NET 8 as we look at the reception and impact of interceptors overall and how it may move forward to being a stable feature.