test: convert WebSocket tests to in-memory transport #1446

Job	Run time
checks / pre-commit	36s
checks / readme-snippets	14s
checks / test (3.10, lowest-direct, ubuntu-latest)	58s
checks / test (3.12, locked, windows-latest)	3m 55s
checks / test (3.11, lowest-direct, windows-latest)	3m 0s
checks / test (3.11, lowest-direct, ubuntu-latest)	55s
checks / test (3.11, locked, ubuntu-latest)	54s
checks / test (3.10, lowest-direct, windows-latest)	4m 22s
checks / test (3.11, locked, windows-latest)	3m 1s
checks / test (3.10, locked, ubuntu-latest)	54s
checks / test (3.14, locked, windows-latest)	3m 12s
checks / test (3.13, locked, ubuntu-latest)	48s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 12s
checks / test (3.14, locked, ubuntu-latest)	2m 8s
checks / test (3.12, lowest-direct, windows-latest)	3m 39s
checks / test (3.10, locked, windows-latest)	3m 18s
checks / test (3.12, locked, ubuntu-latest)	56s
checks / test (3.14, lowest-direct, windows-latest)	2m 41s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 4s
checks / test (3.13, lowest-direct, ubuntu-latest)	55s
checks / test (3.13, locked, windows-latest)	2m 17s
checks / test (3.13, lowest-direct, windows-latest)	2m 53s
all-green	4s
	43m 56s

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