[2.0.21] being able to put items into the dump inventory of assemblers

[Quezler]

at the time of writing there's the control behavior dump inventory at index 7, and the one for changed recipes (and spoilage?) at index 8.

currently both of them read as #length 0 (when they are empty ofc) and .insert() does not work on them, it would be nice if insert worked.
(insert does work if there is already a non full stack of that item in either of the "trash" inventories, but you currently cannot add new items/slots to it)