op-e2e: bump gas limit so its safe

The gas limit must be set to 30 million to ensure that
the default deposit gas market config is safe to use.
This was missed when
https://github.com/ethereum-optimism/optimism/pull/5233 was merged.

op-e2e/system_test.go

@@ -304,7 +304,7 @@ func TestPendingGasLimit(t *testing.T) {
 	cfg := DefaultSystemConfig(t)
 
 	// configure the L2 gas limit to be high, and the pending gas limits to be lower for resource saving.
-	cfg.DeployConfig.L2GenesisBlockGasLimit = 20_000_000
+	cfg.DeployConfig.L2GenesisBlockGasLimit = 30_000_000
 	cfg.GethOptions["sequencer"] = []GethOption{
 		func(ethCfg *ethconfig.Config, nodeCfg *node.Config) error {
 			ethCfg.Miner.GasCeil = 10_000_000
@@ -342,8 +342,8 @@ func TestPendingGasLimit(t *testing.T) {
 	for {
 		checkGasLimit(l2Seq, big.NewInt(-1), 10_000_000)
 		checkGasLimit(l2Verif, big.NewInt(-1), 9_000_000)
-		checkGasLimit(l2Seq, nil, 20_000_000)
-		latestVerifHeader := checkGasLimit(l2Verif, nil, 20_000_000)
+		checkGasLimit(l2Seq, nil, 30_000_000)
+		latestVerifHeader := checkGasLimit(l2Verif, nil, 30_000_000)
 
 		// Stop once the verifier passes genesis:
 		// this implies we checked a new block from the sequencer, on both sequencer and verifier nodes.