Fix unneccessary black lines when settings control is null

Author: Jack251970

Flow.Launcher.Core/Plugin/JsonRPCPluginSettings.cs

@@ -112,7 +112,7 @@ public void Save()
         public Control CreateSettingPanel()
         {
             if (Settings == null || Settings.Count == 0)
-                return new();
+                return null;
 
             var settingWindow = new UserControl();
             var mainPanel = new Grid { Margin = settingPanelMargin, VerticalAlignment = VerticalAlignment.Center };

Flow.Launcher/ViewModel/PluginViewModel.cs

@@ -90,7 +90,7 @@ public bool IsExpanded
         private Control _bottomPart2;
         public Control BottomPart2 => IsExpanded ? _bottomPart2 ??= new InstalledPluginDisplayBottomData() : null;
 
-        public bool HasSettingControl => PluginPair.Plugin is ISettingProvider;
+        public bool HasSettingControl => PluginPair.Plugin is ISettingProvider settingProvider && settingProvider.CreateSettingPanel() != null;
         public Control SettingControl
             => IsExpanded
                 ? _settingControl