CmdPal: Remove duplicate HideWindow call in MainWindow .ctor (#43360)

## Summary of the Pull Request

Refer to the title. Calling this here will just log an error. Another
HideWindow is at the end of the constructor, so the behavior remains
unchanged.

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## PR Checklist

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## Detailed Description of the Pull Request / Additional comments

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src/modules/cmdpal/Microsoft.CmdPal.UI/MainWindow.xaml.cs

@@ -68,7 +68,6 @@ public sealed partial class MainWindow : WindowEx,
     public MainWindow()
     {
         InitializeComponent();
-        HideWindow();
 
         _hwnd = new HWND(WinRT.Interop.WindowNative.GetWindowHandle(this).ToInt32());