You can now throw things from behind tables (#3537)

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## About The Pull Request
You can now throw things from behind flipped tables. 
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documented or this can delay review and even discourage maintainers from
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## Why It's Good For The Game
You would think that being adjacent to a supposedly defensive thing
would at least let you throw things over it. Like sandbags. Or
barricades.
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worth adding. -->

## Changelog

:cl:
add: Flipped tables actually let you throw things over them now.
/:cl:

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code/game/objects/structures/table_flipped.dm

@@ -7,6 +7,7 @@
 	density = TRUE
 	layer = ABOVE_MOB_LAYER
 	opacity = FALSE
+	pass_flags_self = LETPASSTHROW
 	var/table_type = /obj/structure/table
 
 /obj/structure/flippedtable/Initialize()
@@ -54,6 +55,8 @@
 			return
 	if(istype(exiter, /obj/projectile))
 		return
+	if(istype(exiter, /obj/item))
+		return
 	if(direction == table_dir)
 		exiter.Bump(src)
 		return COMPONENT_ATOM_BLOCK_EXIT