Pull changes in ElectronPhotonVariableCorrectionTool from master to 21.2
Several updates have been made to the master version of ElectronPhotonVariableCorrectionTool: !40857 (merged) and !41558 (merged).
This MR applies the same changes to the 21.2 version, in order too keep the tools synchronized.
Tagging @brendlin for awareness, as well as @jdevivi, @jmaurer and @jpoveda.
Edited by Nils Gillwald