CI: make LocalIncomingServerSessionTest robust against async session timing
`LocalIncomingServerSessionTest` had an intermittent CI failure caused by a race in session lifecycle observation. In successful auth scenarios, the test asserted
`result.isClosed() == false` immediately after connection setup, but session registration/auth/close transitions are asynchronous. This occasionally produced false negatives (`expected false but was true`) even when protocol behavior was correct.
Replace brittle point-in-time checks with Awaitility-based eventual assertions:
- resolve the last received stream ID once;
- for successful outcomes, wait until the incoming session for that stream ID is present and matches expected auth/encryption characteristics;
- remove immediate `isClosed()` assertions that are timing-sensitive and not core to what this test needs to validate.
- replace wildcard imports with explicit imports
- extract repeated encrypted/authenticated/TLS assertions into helper
- add assertion messages for clearer CI failure diagnostics
- improve async robustness with Awaitility-based retriable assertions
- verify OF-1913 stream restart metadata via retriable checks
- add helper javadocs and synchronized list snapshot utility
- keep stream-id-first session lookup with domain fallback to reduce race flakiness
This keeps functional coverage intact (including auth method and TLS protocol checks) while eliminating flaky failures due to timing races in CI.
