op-deployer: integration-test uses wrong chainID for dev keys

See https://github.com/ethereum-optimism/optimism/blob/0f476b44a3a284855361685b97baeb4bfb26729b/op-deployer/pkg/deployer/integration_test/apply_test.go#L666

All the keys, and the addresses derived from them, that are created in `newChainIntent` should be unique to the L2, not the L1!

But the function applies the L1 chain ID instead. If this intent were used for different L2s, all L2s would end up with the same operator addresses.

For an isolated test of one chain it may not be a problem, but since documentation is sparse, fixing it would set the right example and help avoid future mistakes by copies of this code.