fix (script): use docker internal port

[BlankerL]

The original script was using public ports instead of internal docker ports. However, the l2_execution_engine relies on the internal docker IP of simple-taiko-node-l2_execution_engine, so it should be using internal docker ports as well.

Originally, if you change the default ports PORT_L2_EXECTION_ENGINE_HTTP and PORT_L2_EXECTION_ENGINE_WS in .env file, the prover relayer could not connect to the execution engine as it connects to the ports in .env file. However, it should connect to 8545 and 8546 to work properly.

[davidtaikocha]

Merged, thanks for the contribution!