sdk/program: switch allow to mod-level for integer_arithmetic lint

sdk/program/src/lib.rs

@@ -1,6 +1,5 @@
 #![cfg_attr(RUSTC_WITH_SPECIALIZATION, feature(specialization))]
 #![cfg_attr(RUSTC_NEEDS_PROC_MACRO_HYGIENE, feature(proc_macro_hygiene))]
-#![allow(clippy::integer_arithmetic)]
 
 // Allows macro expansion of `use ::solana_program::*` to work within this crate
 extern crate self as solana_program;