add horizontal and vertical options for MousePointerCrosshairs (#41789)

## Summary of the Pull Request
This PR addresses two logged issues for MousePointerCrosshairs, these
are:
https://github.com/microsoft/PowerToys/issues/24944 
https://github.com/microsoft/PowerToys/issues/31817

## PR Checklist

- [x] Closes: #24944, #31817
- [x] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [x] **Tests:** Added/updated and all pass
- [x] **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

## Detailed Description of the Pull Request / Additional comments
The PR adds a new combo box to MousePointerCrosshairs XAML options, this
gives the option for 'both', 'vertical only' or 'horizontal only'. The
default option is 'both' which mirrors the existing behavior.

## Validation Steps Performed
Validation has been completed on two separate PCs, a Surface laptop 7
Pro and a Dell Workstation.

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

src/settings-ui/Settings.UI.Library/MousePointerCrosshairsProperties.cs

@@ -40,6 +40,9 @@ namespace Microsoft.PowerToys.Settings.UI.Library
         [JsonPropertyName("crosshairs_border_size")]
         public IntProperty CrosshairsBorderSize { get; set; }
 
+        [JsonPropertyName("crosshairs_orientation")]
+        public IntProperty CrosshairsOrientation { get; set; }
+
         [JsonPropertyName("crosshairs_auto_hide")]
         public BoolProperty CrosshairsAutoHide { get; set; }
 
@@ -68,6 +71,7 @@ namespace Microsoft.PowerToys.Settings.UI.Library
             CrosshairsThickness = new IntProperty(5);
             CrosshairsBorderColor = new StringProperty("#FFFFFF");
             CrosshairsBorderSize = new IntProperty(1);
+            CrosshairsOrientation = new IntProperty(0); // Default to both (0=Both, 1=Vertical, 2=Horizontal)
             CrosshairsAutoHide = new BoolProperty(false);
             CrosshairsIsFixedLengthEnabled = new BoolProperty(false);
             CrosshairsFixedLength = new IntProperty(1);