Fix test wt_close_session_cannot_be_sent_at_once inn sessions.rs

[MayyaSunil]

The test panics with the below error:

---- features::extended_connect::tests::webtransport::sessions::wt_close_session_cannot_be_sent_at_once stdout ----
thread 'features::extended_connect::tests::webtransport::sessions::wt_close_session_cannot_be_sent_at_once' panicked at 'called `Result::unwrap()` on an `Err` value: InvalidStreamId', neqo-http3/src/features/extended_connect/tests/webtransport/mod.rs:278:14
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

failures:
    features::extended_connect::tests::webtransport::sessions::wt_close_session_cannot_be_sent_at_once

The issue is created to track the bug.

[larseggert]

OBE? Tests no longer panic in this way.

[larseggert]

@MayyaSunil OBE?

[larseggert]

Closing this for now as OBE. Reopen if it reoccurs.

[larseggert]

Reopening, because I realized the reason the test was not failing was that it had been marked #[ignore].

[larseggert]

CC @jesup