Investigate and fix TaskRegistry infinite loop due to Dictionary concurrency issue

### Context

Unguarded concurrent access to Dictionary can lead to infinite loop on reading when the underlying data has been changed (https://www.tessferrandez.com/blog/2009/12/21/high-cpu-in-net-app-using-a-static-generic-dictionary.html)

We've had similiar issues in `TaskRegistry` that we've been fixing recently: https://github.com/dotnet/msbuild/pull/9032

Some of the issues still remain:

https://prism.vsdata.io/failuregroup/?query=ch%3Drelease%20r%3D17.12&eventType=cpu&failureType=dualdirection&failureGroupId=60ca1d45-9aa0-48e0-b9a9-f149de98ab4e

### Goal

Investigate where exactly is the issue occuring.
Investigate why it is still possible to have concurrent access to the Dictionaries within `TaskRegistry`
Attempt to prevent those without blindly making Dictionaries concurrent (as we should understand the concurency model of our structures, and TaskRegistry was understood to be immutable after initial creation)