Revert "Add stamped requisition forms now give bonus credits (#66230)" (#66851)

This reverts commit f021767645.

This reverts commit f021767 from:

    Add stamped requisition forms now give bonus credits #66230

This bug was encountered when we were testing this PR but I thought it got fixed.
Why It's Good For The Game

Cargo crates will now reappear.

code/modules/paperwork/paper.dm

@@ -63,6 +63,7 @@
 
 /obj/item/paper/Destroy()
 	stamps = null
+	stamped = null
 	form_fields = null
 	stamped = null
 	. = ..()
@@ -397,29 +398,6 @@
 		to_chat(usr, pick("You try to stamp but you miss!", "There is no where else you can stamp!"))
 		return FALSE
 
-/**
- * is_approved
- *
- * To determine if a paper has the correct stamp. If no department stamp is specified then the
- * regular granted stamp (/obj/item/stamp) is checked
- *
- * Arguments:
- * * department (optional) - The department stamp we are checking for
- */
-/obj/item/paper/proc/is_approved(department_stamp)
-	if(department_stamp)
-		return stamped && (department_stamp in stamped)
-	else
-		return stamped && ("stamp-ok" in stamped)
-
-/**
- * is_denied
- *
- * To determine if a paper has the DENIED stamp
- */
-/obj/item/paper/proc/is_denied()
-	return stamped && ("stamp-deny" in stamped)
-
 /obj/item/paper/ui_act(action, params, datum/tgui/ui)
 	. = ..()
 	if(.)