Make sure that UDP transports remain open when UDP listener is closed

[OlivierHecart]

No description provided.

[github-actions]

PR missing one of the required labels: {'dependencies', 'bug', 'new feature', 'documentation', 'enhancement', 'internal', 'breaking-change'}

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
464	1	463	0

View the top 1 failed test(s) by shortest run time

zenoh-transport::unicast_transport::transport_unicast_ws_only_with_lowlatency_transport::case_3

Stack Traces | 65.3s run time

thread 'transport_unicast_ws_only_with_lowlatency_transport::case_3' panicked at io\zenoh-transport\tests\unicast_transport.rs:445:5:
called `Result::unwrap()` on an `Err` value: Elapsed(())
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

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[Mallets]

If it should fail and we are expecting a different timeout, I rather change the timeout in the config.
The expected error should be clear and not ambiguous.

E.g., I would rather explicitly set the open_timeout config parameter to ensure the timeout happens internally and the open_transport_unicast() returns an error.

zenoh/DEFAULT_CONFIG.json5

Line 450 in 0e0c5d9

open_timeout: 10000,