Limitless active_connection_id_limit

[QUICTester]

Hi,

During testing commit https://github.com/p-quic/pquic/commit/841c82289b23d32c28723a0175654ecc6baeae08, we discovered that the PQUIC server does not set a limit for its active_connection_id_limit transport parameter and able to process up to 1000 NEW_CONNECTION_ID frame.

According to RFC 9000, if the value of active_connection_id_limit is absent, a default limit of 2 is assumed. This means that if the number of active connection IDs exceeds the value advertised in its active_connection_id_limit transport parameter (which is 2 in this case), the server MUST close the connection with an error of type CONNECTION_ID_LIMIT_ERROR.

[mpiraux]

Could you test #39 as a potential fix ?

[QUICTester]

Yup, the server response with correct message now.