Fixed initializeWithCallback func in LibsodiumInitializer. Note: now it returns a JsString "null" instead of nothing

multiplatform-crypto-libsodium-bindings/src/wasmJsMain/kotlin/com/ionspin/kotlin/crypto/JsSodiumLoader.kt

@@ -52,7 +52,7 @@ object JsSodiumLoader {
 
     fun loadWithCallback(doneCallback: () -> (JsAny)) {
         if (!getSodiumLoaded()) {
-            _libsodiumPromise.then {
+            _libsodiumPromise.then<JsAny> {
                 sodium_init()
                 sodiumLoaded = true
                 doneCallback.invoke()

multiplatform-crypto-libsodium-bindings/src/wasmJsMain/kotlin/com/ionspin/kotlin/crypto/LibsodiumInitializer.kt

@@ -21,10 +21,12 @@ actual object LibsodiumInitializer {
         isPlatformInitialized = true
     }
 
+
     actual fun initializeWithCallback(done: () -> Unit) {
         JsSodiumLoader.loadWithCallback {
             isPlatformInitialized = true
             done()
+            "null".toJsString()
         }
     }