un-needed dynamic_casts -> static_casts in SCT_FrontEnd
When profiling ITkStrip digitization with VTune it was noticed that a small but non-negligible amount of time was spent in these dynamic_casts, and this is presumably the case also for SCT.
They do not seem necessary (in one case there is anyway no check, there should not be any elements in the container for which the cast fails, and in the case there was, it would be better for the job to crash than to gracefully continue with invalid inputs).
No change is observed when running RunTier0Tests.py