Output is incorrect when run with `--port=0`

[jspeiser]

What happened?

When the emulator is started with --port=0 on a Linux machine it should be assigned a random available port by the system. I think this is happening, but the "server listening at" logs happen before the port is assigned:

➜ ~/emulator --project=test-project --dataset=test_dataset --log-level=debug --port=0 --grpc-port=0
[bigquery-emulator] REST server listening at 0.0.0.0:0
[bigquery-emulator] gRPC server listening at 0.0.0.0:0

What did you expect to happen?

I expected the output to have the actual port being listened to. It seems like this should be available.

How can we reproduce it (as minimally and precisely as possible)?

Start the emulator with --port=0.

Anything else we need to know?

No response