FunctionFitting Code formatting/whitespace changes only
Remove dead variable, fitMethod and reformat code.

The whole (algorithm == null) side of the if was essentially unreachable
and had it been reached, then no fit would have run. The fallback case
has correctly been changed to run APACHENELDERMEAD if the algoId is
not recongnized.
When performing fit in function fitting, operate on a copy of the input functions

We need to use a copy because the fitting function modifies the parameters
of the functions passed into it. If we don't do that, the act of running
the fitting clobbers our input values.

This fix is related to the changes in 2397437 which introduced the regression
Merge branch 'DAWNSCI-5676-function-fitting'