Fix fillig event header in EFTracking FPGASim
In the previous MR !64464 (merged) the code was changed so that the events (hits) can be read from the SG (in addition to reading it from wrappers). However, the infomation was lost due to a bug fixed now. An incorrect event heder was filled.
Also added documentation on how to run the transform.
Edited by Tomasz Bold