Update halos on incrementalCalvingThickness

Replace the allocatable array dCalvingThickness with a Registry
variable incrementalCalvingThickness, and update halos after calling
li_apply_front_ablation_velocity and before subtracting from ice thickness.

Author: trhille

components/mpas-albany-landice/src/Registry.xml

@@ -1254,6 +1254,9 @@ is the value of that variable from the *previous* time level!
                 <var name="calvingFrontMask" type="integer" dimensions="nCells Time" units="none" time_levs="1"
                         description="mask of the calving front position on cells"
                 />
+                <var name="incrementalCalvingThickness" type="real" dimensions="nCells Time" units="m" time_levs="1"
+                        description="thickness of ice that calves in a given step. Maybe be updated multiple times per time step to calculate calvingThickness."
+                />
                 <var name="calvingThickness" type="real" dimensions="nCells Time" units="m" time_levs="1"
                         description="thickness of ice that calves on a given timestep (less than or equal to ice thickness)"
                 />