Don't automatically fall back to automatic port if web socket port is already in use, only recommend using 0 instead

[Wumpf]

What

• Fixes When using rr.serve and specifying ports, they are chosen at random if they are already occupied. #6222

Running this scrip twice:

#!/usr/bin/env python3
import rerun as rr
import time

def main() -> None:
    rr.init("rerun_example_serve")
    rr.serve(web_port=57158, ws_port=57159)

    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        print("Ctrl-C received. Exiting.")

if __name__ == "__main__":
    main()

Gives now this error:

Traceback (most recent call last):
  File "/Users/andreas/dev/rerun-io/rerun/test.py", line 18, in <module>
    main()
  File "/Users/andreas/dev/rerun-io/rerun/test.py", line 8, in main
    rr.serve(web_port=57158, ws_port=57159)
  File "/Users/andreas/dev/rerun-io/rerun/rerun_py/rerun_sdk/rerun/sinks.py", line 252, in serve
    bindings.serve(
RuntimeError: Failed to bind to WebSocket port 57159 since the address is already in use. Use port 0 to let the OS choose a free port.

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