Bump Microsoft.WindowsAppSDK from 2.3.1 to 2.4.0 (#1171)

---
updated-dependencies:
- dependency-name: Microsoft.WindowsAppSDK
  dependency-version: 2.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]

Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
 
   <PropertyGroup>
-    <MicrosoftWindowsAppSDKVersion>2.3.1</MicrosoftWindowsAppSDKVersion>
+    <MicrosoftWindowsAppSDKVersion>2.4.0</MicrosoftWindowsAppSDKVersion>
     <MicrosoftWindowsSdkBuildToolsVersion>10.0.28000.2526</MicrosoftWindowsSdkBuildToolsVersion>
   </PropertyGroup>