fix: cosmos balance parsing (#3036)

@tkporter reported that cosmos balance strings were being interpreted as
hex when parsed, causing them to appear much larger. This fixes by
parsing as decimal.

Tested manually by checking the metrics endpoint.

rust/chains/hyperlane-cosmos/src/providers/grpc.rs

@@ -238,7 +238,7 @@ impl WasmGrpcProvider {
             .balance
             .ok_or_else(|| ChainCommunicationError::from_other_str("account not present"))?;
 
-        Ok(balance.amount.parse()?)
+        Ok(U256::from_dec_str(&balance.amount)?)
     }
 
     /// Queries an account.