Fix an intermittent hang in TRL's colocated vLLM generation when a PEFT model uses tensor parallelism across…

Fix an intermittent hang in TRL's colocated vLLM generation when a PEFT model uses tensor parallelism across…: a task in HF ML Tasksmith (Harbor dataset). Make this transition use the GPU assigned to the local worker explicitly and complete safely before inference begins. Keep the existing…