fix: support propagation for each destination in generic_send.py
fix: support propagation for each destination in generic_send.py

- If service script generates data specific to each destination,
  we must use fallback to "all" if generated data is actually shared
  between multiple destinations.

CESNET/perun-services,zlamalp/perun-services,CESNET/perun-services,zlamalp/perun-services,CESNET/perun-services,zlamalp/perun-services,zlamalp/perun-services,CESNET/perun-services