Investigate and fix TaskRegistry infinite loop due to Dictionary concurrency issue

[JanKrivanek]

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: #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)