CmdPal: Respect Ignore shortcut in fullscreen mode when using the low-level keyboard hook (#41402)

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fix/what does it change/how was it tested (even manually, if necessary)?
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## Summary of the Pull Request

Refactors the logic that determines whether to ignore keyboard shortcuts
while in fullscreen mode. The check is now handled in `HandleSummon`,
which centralizes all precondition checks before delegating the actual
summoning to `HandleSummonCore`.

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## PR Checklist

- [x] Closes: #41265
- [ ] **Communication:** I've discussed this with core contributors
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- [ ] **Tests:** Added/updated and all pass
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## Detailed Description of the Pull Request / Additional comments

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## Validation Steps Performed

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

@@ -635,6 +635,20 @@ public sealed partial class MainWindow : WindowEx,
     }
 
     private void HandleSummon(string commandId)
+    {
+        if (_ignoreHotKeyWhenFullScreen)
+        {
+            // If we're in full screen mode, ignore the hotkey
+            if (WindowHelper.IsWindowFullscreen())
+            {
+                return;
+            }
+        }
+
+        HandleSummonCore(commandId);
+    }
+
+    private void HandleSummonCore(string commandId)
     {
         var isRootHotkey = string.IsNullOrEmpty(commandId);
         PowerToysTelemetry.Log.WriteEvent(new CmdPalHotkeySummoned(isRootHotkey));
@@ -694,15 +708,6 @@ public sealed partial class MainWindow : WindowEx,
                     var hotkeyIndex = (int)wParam.Value;
                     if (hotkeyIndex < _hotkeys.Count)
                     {
-                        if (_ignoreHotKeyWhenFullScreen)
-                        {
-                            // If we're in full screen mode, ignore the hotkey
-                            if (WindowHelper.IsWindowFullscreen())
-                            {
-                                return (LRESULT)IntPtr.Zero;
-                            }
-                        }
-
                         var hotkey = _hotkeys[hotkeyIndex];
                         HandleSummon(hotkey.CommandId);
                     }