dillon1000/react

[Transition Tracing] Change Transition Type Passed Pending Transitions (#24856)

This PR changes the type of the object we store in the pending transitions callbacks map. Previously, we were recreating the transition object that we initially created during `startTransition`. However, we can actually reuse the object instead (and it also gives us a stable way to identify a transition). This PR changes the implementation to reuse the transition object instead of creating a new one