fix temporary password not update right now when length changed

Signed-off-by: 21pages <pages21@163.com>

flutter/lib/models/server_model.dart

@@ -217,6 +217,9 @@ class ServerModel with ChangeNotifier {
       update = true;
     }
     if (_temporaryPasswordLength != temporaryPasswordLength) {
+      if (_temporaryPasswordLength.isNotEmpty) {
+        bind.mainUpdateTemporaryPassword();
+      }
       _temporaryPasswordLength = temporaryPasswordLength;
       update = true;
     }