[CmdPal] Fix filters visibility on non-ListPage (#42828)

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## Summary of the Pull Request
This PR aims to fix the issue where filters from a ListPage remain
visible when navigating to other pages.
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## PR Checklist

- [x] Closes: #42827 
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **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
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for new binaries and localization folder
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## Detailed Description of the Pull Request / Additional comments
### Before:

![FiltersIssue](https://github.com/user-attachments/assets/b0ad6059-9a11-4e12-821d-7202358e25bb)

### After:

![FiltersFix](https://github.com/user-attachments/assets/b9ee71ee-cb5d-4ef9-b9fc-bc2e2a710b5c)

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Co-authored-by: Jiří Polášek <me@jiripolasek.com>

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/FiltersDropDown.xaml

@@ -77,7 +77,7 @@
         SelectedValue="{x:Bind ViewModel.CurrentFilter, Mode=OneWay}"
         SelectionChanged="FiltersComboBox_SelectionChanged"
         Style="{StaticResource ComboBoxStyle}"
-        Visibility="{x:Bind ViewModel.ShouldShowFilters, Mode=OneWay, Converter={StaticResource BoolToVisibilityConverter}}">
+        Visibility="{x:Bind ViewModel.ShouldShowFilters, Mode=OneWay, Converter={StaticResource BoolToVisibilityConverter}, FallbackValue=Collapsed}">
         <ComboBox.ItemContainerStyle>
             <Style BasedOn="{StaticResource DefaultComboBoxItemStyle}" TargetType="ComboBoxItem">
                 <Setter Property="MinHeight" Value="0" />