CmdPal: Remove fallbacks from the home page when there's no query (#44005)

## Summary of the Pull Request

This PR stops fallback commands from showing on the homepage when
there’s no query, with the reasons detailed in the linked issue.

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## PR Checklist

- [x] Closes: #44004 
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- [ ] **Communication:** I've discussed this with core contributors
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- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

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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.ViewModels/Commands/MainListPage.cs

@@ -161,7 +161,7 @@ public partial class MainListPage : DynamicListPage,
             {
                 return _tlcManager
                     .TopLevelCommands
-                    .Where(tlc => !string.IsNullOrEmpty(tlc.Title))
+                    .Where(tlc => !tlc.IsFallback && !string.IsNullOrEmpty(tlc.Title))
                     .ToArray();
             }
         }