fix(react): Preserve parent path prefix for descendant route names in react-router

[s1gr1d]

We store the routes in allRoutes which is a flat Set mixing every mounted <Routes> subtree. Because child effects fire before parent effects, the descendant <SentryRoutes>'s routes (:id with its nested .children :sub) are flattened into allRoutes, keeping .children.

This PR adds reconstructNameFromDescendantParent that's basically a band-aid for this specific problem. The architecture of how we save this (in a flat allRoutes) is the underlying problem. I will modify this architecture in a follow-up PR as this would go beyond scope of this fix.

Closes #22194