Fix build issue

Author: Jack251970

Flow.Launcher.Core/Plugin/PluginManager.cs

@@ -6,6 +6,7 @@
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
+using System.Windows.Input;
 using Flow.Launcher.Core.ExternalPlugins;
 using Flow.Launcher.Infrastructure;
 using Flow.Launcher.Infrastructure.DialogJump;