Fix FCS pieciewise linear interpolation lookup at edges
This MR fixes a problem, where the interpolation lookup at the edges of logEkin led to ROOT::Math::GSLInterpolator::Eval:0
runtime warnings. This happened because in L39 m_MinMaxlogEkin
is casted to float so that the minimum and maxium logEkin values did not exactly correspond to the edges which the interpolation holds.
Edited by Joshua Falco Beirer