fix: do not allow to pass A&B custom options to backend.run()

[gschurck]

The Alice & Bob custom options of Processors like average_nb_photons are not allowed for backend.run() with local provider because they will be ignored. They should be passed to get_backend() instead.

[alxthm]

Thanks ! it would be nice if qiskit itself raised an error when specifying unsupported options to the execution backend .run method, but I don't see a way to do it (with the AerSimulator for instance)

This seems like an easy and simple safeguard to catch at least some mistakes

[gschurck]

Yes, it's the simpler workaround I think. I chose to get the parameters dynamically from the processor function, so we don't have to maintain a string list of the parameters that could become out of sync. I didn't know if it was better to do it in __init__() or in run(), but at least here it runs this code only when needed.