chore(deps): update dependency microsoft.windowsappsdk to 1.8.250907003 (#4137)

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This PR contains the following updates:

| Package | Change | Age | Confidence |
|---|---|---|---|
|
[Microsoft.WindowsAppSDK](https://redirect.github.com/microsoft/windowsappsdk)
| `1.7.250606001` -> `1.8.250907003` |
[![age](https://developer.mend.io/api/mc/badges/age/nuget/Microsoft.WindowsAppSDK/1.8.250907003?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/nuget/Microsoft.WindowsAppSDK/1.7.250606001/1.8.250907003?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

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src/Directory.Packages.props

@@ -71,7 +71,7 @@
     <PackageVersion Include="Xamarin.AndroidX.Preference" Version="1.2.1.15" />
   </ItemGroup>
   <ItemGroup Condition="'$(UseMaui)' != 'true'">
-    <PackageVersion Include="Microsoft.WindowsAppSDK" Version="1.7.250606001" />
+    <PackageVersion Include="Microsoft.WindowsAppSDK" Version="1.8.250907003" />
   </ItemGroup>
   <ItemGroup Condition="$(TargetFramework.StartsWith('net4'))">
     <PackageVersion Include="System.ValueTuple" Version="4.6.1" />