SampleHandler: Update for root 6.33. (ATLASG-2814)
root 6.33 drops TPython::Eval. One is instead meant to use Python::Exec returning the result via a std::any.
Fixes failure in dev3lcg.
root 6.33 drops TPython::Eval. One is instead meant to use Python::Exec returning the result via a std::any.
Fixes failure in dev3lcg.