Cleanup more callback things (#3051)

Looks quite stable on my computers, so maybe we give it a try?

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Co-authored-by: veeck <michael@veeck.de>

js/node_helper.js

@@ -13,9 +13,8 @@ const NodeHelper = Class.extend({
 		Log.log("Initializing new module helper ...");
 	},
 
-	loaded(callback) {
+	loaded() {
 		Log.log(`Module helper loaded: ${this.name}`);
-		callback();
 	},
 
 	start() {