fix: use Closure::wrap instead of Closure::once for wasm-bindgen compatibility

Closure::once was added in wasm-bindgen 0.2.93, but many projects still use
older versions. Changed to use Closure::wrap with FnMut which works across
all wasm-bindgen versions.

Fixes compilation error in River and other projects using older wasm-bindgen.

Author: sanity

rust/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "freenet-stdlib"
-version = "0.1.20"
+version = "0.1.21"
 edition = "2021"
 rust-version = "1.71.1"
 publish = true

rust/src/client_api/browser.rs

@@ -88,9 +88,9 @@ impl WebApi {
         conn.set_onerror(Some(onerror_callback.as_ref().unchecked_ref()));
         onerror_callback.forget();
 
-        let onopen_callback = Closure::<dyn FnOnce()>::once(move || {
+        let onopen_callback = Closure::wrap(Box::new(move || {
             onopen_handler();
-        });
+        }) as Box<dyn FnMut()>);
         // conn.add_event_listener_with_callback("open", onopen_callback.as_ref().unchecked_ref());
         conn.set_onopen(Some(onopen_callback.as_ref().unchecked_ref()));
         onopen_callback.forget();