feat(core): Remove getter and setter for connectionSettings

example/lib/main.dart

@@ -108,12 +108,10 @@ class _MyHomePageState extends State<MyHomePage> {
     setState(() {
       loading = true;
     });
-    connection.setConnectionSettings(
-      ConnectionSettings(
-        jid: JID.fromString(jidController.text),
-        password: passwordController.text,
-        useDirectTLS: true,
-      ),
+    connection.connectionSettings = ConnectionSettings(
+      jid: JID.fromString(jidController.text),
+      password: passwordController.text,
+      useDirectTLS: true,
     );
     final result = await connection.connect(waitUntilLogin: true);
     setState(() {