Fix ProcessExitedException

✅ Solution

ProcessExitedException in PyTorch Lightning tests often arises from unexpected process termination during multi-processing scenarios such as `ddp_fork`. This commonly stems from resource exhaustion, unhandled exceptions within child processes, or conflicts with system-level libraries. To resolve it, ensure adequate system resources (RAM, CPU), implement robust error handling within the child processes, and check for library incompatibilities, especially with multiprocessing on MacOS.