test: fix WS test port race; narrow to single smoke test covering both transport ends #1517

Job	Run time
checks / pre-commit	33s
checks / readme-snippets	14s
checks / test (3.11, lowest-direct, windows-latest)	3m 12s
checks / test (3.10, locked, windows-latest)	2m 11s
checks / test (3.11, lowest-direct, ubuntu-latest)	57s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 4s
checks / test (3.12, locked, windows-latest)	3m 47s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 0s
checks / test (3.10, lowest-direct, windows-latest)	2m 18s
checks / test (3.11, locked, ubuntu-latest)	51s
checks / test (3.12, lowest-direct, windows-latest)	3m 42s
checks / test (3.11, locked, windows-latest)	2m 25s
checks / test (3.13, locked, ubuntu-latest)	48s
checks / test (3.10, locked, ubuntu-latest)	52s
checks / test (3.13, lowest-direct, windows-latest)	2m 33s
checks / test (3.13, locked, windows-latest)	2m 22s
checks / test (3.12, locked, ubuntu-latest)	58s
checks / test (3.13, lowest-direct, ubuntu-latest)	52s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 15s
checks / test (3.14, lowest-direct, windows-latest)	2m 20s
checks / test (3.14, locked, ubuntu-latest)	2m 25s
checks / test (3.14, locked, windows-latest)	3m 14s
all-green	3s
	39m 56s

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