Fix validate_input_col for nn.Module or Callable (#96213)
Forward fix the problem introduced in https://github.com/pytorch/pytorch/pull/95067
Not all `Callable` objects have `__name__` implemented. Using `repr` as the backup solution to get function name or reference.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/96213
Approved by: https://github.com/NivekT
