Add max gas limit check in ante handler (#532)

## Describe your changes and provide context
Context for this change is from an immunefi bug report:

> when process the proposal block, sei protocol will check the gas fee
is valid or not, if totalGasWanted is bigger than
ctx.ConsensusParams().Block.MaxGas will return false,
> 
> And then in the tendermint will reject the proposal in validblock, but
the bad thing is the sei protcol try to process this block in a loop and
will not produce the new block. so will lead to the
> 
> sei network not being able to confirm new transactions.

## Testing performed to validate your change

simapp/test_helpers.go

@@ -39,7 +39,7 @@ import (
 var DefaultConsensusParams = &tmproto.ConsensusParams{
 	Block: &tmproto.BlockParams{
 		MaxBytes: 200000,
-		MaxGas:   2000000,
+		MaxGas:   100000000,
 	},
 	Evidence: &tmproto.EvidenceParams{
 		MaxAgeNumBlocks: 302400,

x/auth/ante/setup.go

@@ -51,6 +51,13 @@ func (sud SetUpContextDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate
 
 	newCtx = sud.gasMeterSetter(simulate, ctx, gasTx.GetGas(), tx)
 
+	if cp := ctx.ConsensusParams(); cp != nil && cp.Block != nil {
+		// If there exists a maximum block gas limit, we must ensure that the tx
+		// does not exceed it.
+		if cp.Block.MaxGas > 0 && gasTx.GetGas() > uint64(cp.Block.MaxGas) {
+			return newCtx, sdkerrors.Wrapf(sdkerrors.ErrOutOfGas, "tx gas wanted %d exceeds block max gas limit %d", gasTx.GetGas(), cp.Block.MaxGas)
+		}
+	}
 	// Decorator will catch an OutOfGasPanic caused in the next antehandler
 	// AnteHandlers must have their own defer/recover in order for the BaseApp
 	// to know how much gas was used! This is because the GasMeter is created in