[TASK] Let FluidPages add colPos list item -42

For a while still, Flux won't be able to add this value itself and will live with an "INVALID VALUE" message. However, when EXT:fluidpages is installed the item is easily filled in.
[BUGFIX] Don't force type of argument in colPos list items hook method

I know - this is a potential fugbix (a bug fix which just introduces another problem). However, since the variable is never used, the type is irrelevant - if there are no warnings about interface compliance, of which there were none.