Remove null check from _tabsTracker.Dispose() call

The null-conditional operator was removed from _tabsTracker.Dispose()
in the Dispose() method, assuming _tabsTracker is always non-null
when Dispose() is called.

Plugins/Flow.Launcher.Plugin.BrowserBookmark/Main.cs

@@ -265,7 +265,7 @@ public class Main : ISettingProvider, IPlugin, IReloadable, IPluginI18n, IContex
 
     public void Dispose()
     {
-        _tabsTracker?.Dispose();
+        _tabsTracker.Dispose();
         DisposeFileWatchers();
     }