Fix cleuparser indexing with nil

FreshShit/_Shared/CLEUParser.lua

@@ -410,6 +410,8 @@ CLEUParser = {
 	GetOverkill = function(...)
 		local subevent, err = CLEUParser.GetSubevent(...)
 		if err then return 0, string.format("Failed getting subevent due to: %s", err) end
+		if not CLEUEventInfo[subevent] then return 0, "Subevent is not a valid event" end
+		if not CLEUEventInfo[subevent]["overkill"] then return 0, "Overkill is nil or missing" end
 		local val = select(CLEUEventInfo[subevent]["overkill"], ...)
 		if val == nil then return 0, "Overkill is nil or missing" end
 		if type(val) ~= "number" then return 0, "Overkill is not a number" end