chore(deps): update windows sdk & app sdk (#4156)

> [!NOTE]
> Mend has cancelled [the proposed
renaming](https://redirect.github.com/renovatebot/renovate/discussions/37842)
of the Renovate GitHub app being renamed to `mend[bot]`.
> 
> This notice will be removed on 2025-10-07.

<hr>

This PR contains the following updates:

| Package | Change | Age | Confidence |
|---|---|---|---|
| [Microsoft.Windows.SDK.BuildTools](https://aka.ms/WinSDKProjectURL) |
`10.0.26100.4948` -> `10.0.26100.6584` |
[![age](https://developer.mend.io/api/mc/badges/age/nuget/Microsoft.Windows.SDK.BuildTools/10.0.26100.6584?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/nuget/Microsoft.Windows.SDK.BuildTools/10.0.26100.4948/10.0.26100.6584?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
|
[Microsoft.WindowsAppSDK](https://redirect.github.com/microsoft/windowsappsdk)
| `1.8.250907003` -> `1.8.250916003` |
[![age](https://developer.mend.io/api/mc/badges/age/nuget/Microsoft.WindowsAppSDK/1.8.250916003?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/nuget/Microsoft.WindowsAppSDK/1.8.250907003/1.8.250916003?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined),
Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you
are satisfied.

♻ **Rebasing**: Whenever PR is behind base branch, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about these
updates again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/reactiveui/ReactiveUI).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0MS4xMzEuOSIsInVwZGF0ZWRJblZlciI6IjQxLjEzMS45IiwidGFyZ2V0QnJhbmNoIjoibWFpbiIsImxhYmVscyI6WyJEZXBlbmRlbmN5IE1hbmFnZW1lbnQiXX0=-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/Directory.Packages.props

@@ -27,7 +27,7 @@
     <PackageVersion Include="Microsoft.Reactive.Testing" Version="6.0.2" />
     <PackageVersion Include="System.Reactive" Version="6.0.2" />
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="8.0.0" />
-    <PackageVersion Include="Microsoft.Windows.SDK.BuildTools" Version="10.0.26100.4948" />
+    <PackageVersion Include="Microsoft.Windows.SDK.BuildTools" Version="10.0.26100.6584" />
     <PackageVersion Include="Microsoft.Xaml.Behaviors.Wpf" Version="1.1.135" />
     <PackageVersion Include="Mocks.Maui" Version="1.2.5" />
     <PackageVersion Include="Nerdbank.GitVersioning" Version="3.8.118" />
@@ -71,7 +71,7 @@
     <PackageVersion Include="Xamarin.AndroidX.Preference" Version="1.2.1.15" />
   </ItemGroup>
   <ItemGroup Condition="'$(UseMaui)' != 'true'">
-    <PackageVersion Include="Microsoft.WindowsAppSDK" Version="1.8.250907003" />
+    <PackageVersion Include="Microsoft.WindowsAppSDK" Version="1.8.250916003" />
   </ItemGroup>
   <ItemGroup Condition="$(TargetFramework.StartsWith('net4'))">
     <PackageVersion Include="System.ValueTuple" Version="4.6.1" />