[MIRROR] Fix table top deconstruction

[Steals-The-PRs]

Mirrored on Nova: NovaSector/NovaSector#1880
Original PR: tgstation/tgstation#82508

About The Pull Request

Edited: updated changelog, read comments for changes in implementation details

So previously, tables would let you use a wrench to fully deconstruct them, or a screwdriver to take off only their top.
This, however, broke in two different ways in #82280, when their deconstruction logic got changed.

First off, deconstructed tables would only drop the materials for their top and not their frame.
For this, the primary culprit seems to be on line 307:
https://github.com/tgstation/tgstation/blob/c34d56a45b0461f5e0fad3cc75e81580c3357119/code/game/objects/structures/tables_racks.dm#L300-L307
Where new framestack(target_turf, framestackamount) accidentally got an extra indent, and ended up in the less common half of the if-else chain.
Just moving this outside of the if-else chain again fixes it.

Secondly, tables had their own special deconstruction logic, which got 'standardized'.
Issue. This was special to accommodate for having two different deconstruction logics: full or top only.
With deconstruct(...) no longer being overridable, I feel it's awkward to attempt to proxy that information to the new atom_deconstruct(...)
So we introduce a new method, deconstruct_top, for the screwdriver to use, which handles deconstructing only the top.

/obj/structure/table/proc/deconstruct_top()
	var/obj/table_frame = new frame(loc)
	if(obj_flags & NO_DECONSTRUCTION)
		table_frame.obj_flags |= NO_DECONSTRUCTION
	else // Mimic deconstruction logic, only drop our materials without NO_DECONSTRUCTION
		var/turf/target_turf = get_turf(src)
		drop_top_mats(target_turf)
	qdel(src)

Mimicking the NO_DECONSTRUCTION logic of normal deconstruction, and copying over the flag onto its frames if need be.
This fixes screwdriver deconstruction.

Why It's Good For The Game

Fixes #82503.
We can now deconstruct the table top separately again, AND get the right materials back too.

Changelog

🆑 00-Steven, SyncIt21
fix: Wrench table deconstruction gives the right materials again.
fix: Screwdriver table deconstruction only deconstructs the top again.
/:cl: