fix cloned string cleanup

dynamodb/filter.odin

@@ -817,7 +817,7 @@ parse_filter_expression_string :: proc(request_body: []byte) -> (expr: string, o
 		return
 	}
 
-	expr = string(fe_str)
+	expr = strings.clone(string(fe_str))
 	ok = true
 	return
 }