Await async delegates fully in DispatcherHelper

Ensure that async functions invoked via dispatcher are awaited until completion, not just until scheduled, by using double await on InvokeAsync. This prevents premature continuation when the delegate itself is asynchronous.

Flow.Launcher.Core/Resource/DispatcherHelper.cs

@@ -95,7 +95,7 @@ public static class DispatcherHelper
         }
         else
         {
-            await dispatcher.InvokeAsync(func, priority);
+            await await dispatcher.InvokeAsync(func, priority);
         }
     }
 }