Fix crash when pasting item from GeForce Now

Author: Wires77

src/Classes/ItemsTab.lua

@@ -1059,12 +1059,12 @@ function ItemsTabClass:Draw(viewPort, inputEvents)
 		if event.type == "KeyDown" then	
 			if event.key == "v" and IsKeyDown("CTRL") then
 				local newItem = Paste()
-				if newItem:find("{ ", 0, true) then
-					main:OpenConfirmPopup("Warning", "\"Advanced Item Descriptions\" (Ctrl+Alt+c) are unsupported.\n\nAbort paste?", "OK", function()
-						self:SetDisplayItem()
-					end)
-				end
 				if newItem then
+					if newItem:find("{ ", 0, true) then
+						main:OpenConfirmPopup("Warning", "\"Advanced Item Descriptions\" (Ctrl+Alt+c) are unsupported.\n\nAbort paste?", "OK", function()
+							self:SetDisplayItem()
+						end)
+					end
 					self:CreateDisplayItemFromRaw(newItem, true)
 				end
 			elseif event.key == "e" then