We currently set the start/end times for a phase in the resharding coordinator service whenever we transition to a new state.

This function currently only handles the cases when the new state is either `kCloning`, `kApplying`, or `kBlockingWrites`.

We should update this function to properly set the start and end time metrics for all valid state transitions for this service.

Ideally, the function would accept the previous state as well as the next state as parameters, so that we can track each state transition properly.