remove unused NN cluster splitting options from workflow

This MR removes two options which are 1) not used in default reconstruction and 2) no longer supported by the CTIDE group from SiClusterizationFactory and the code which depends on it.

Specifically, the two options removed are:

• Use of NNs which do not take track information as inputs. These perform worse than those which use track information and are not called as part of our current reconstruction.
• Option to do Run 1-style cluster splitting. The availability of this option was seemingly added as a temporary fix for Release 19.1 and is never used so it seems probably okay to remove it now.

We are merging this to 21.0 in advance of one or two more upcoming merge requests which will alter how we evaluate the NNs. Removing the above defunct options will make that migration a lot cleaner since we won't have to add variants for each. Ultimately, parallel changes will need to go into master, but we are starting here because we would like to request some samples with new NNs over the winter break. I attach the frozen T0 test log FrozenT0Test_MR27787.txt as evidence that this doesn't affect default running.

Tagging @gfacini and @rhowen for info.

Cheers, Kate