delete_ns blocks thread indefinitely

[LambdaSpg]

Describe the bug
Calling delete_ns blocks the thread because the RWLock does not get released after going out of scope

To Reproduce

    let io_clone = Arc::new(io.clone());
    io.ns("/", move |socket_ref: SocketRef| {
        info!("Connected!");
        socket_ref.on_disconnect(move || {
            io_clone.delete_ns("/");
            info!("This won't run, because the thread is blocked by RWLock");
        })
    });

Connect a client on '/', disconnect it, and the info won't get called. After that, the server does not work anymore and won't accept new connections.

Expected behavior
The server should continue running like usual

Versions (please complete the following information):

• Socketioxide version: 0.12.0
• Http lib: 0.7.5
• Socket.io client version ^4.7.5

[Totodore]

Hey, indeed, there is a deadlock when you call delete_ns from on_disconnect because the Namespace RwLock is currently being readen. I'll try to fix this ASAP and also add a test case.