Bump Microsoft.ApplicationInsights from 2.12.0 to 2.21.0 (#2881)

Bumps [Microsoft.ApplicationInsights](https://github.com/Microsoft/ApplicationInsights-dotnet) from 2.12.0 to 2.21.0.
- [Release notes](https://github.com/Microsoft/ApplicationInsights-dotnet/releases)
- [Changelog](https://github.com/microsoft/ApplicationInsights-dotnet/blob/main/CHANGELOG.md)
- [Commits](microsoft/ApplicationInsights-dotnet@2.12.0...2.21.0)

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

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Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

MainDemo.Uwp/MainDemo.Uwp.csproj

@@ -132,7 +132,7 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.ApplicationInsights">
-      <Version>2.12.0</Version>
+      <Version>2.21.0</Version>
     </PackageReference>
     <PackageReference Include="Microsoft.ApplicationInsights.PersistenceChannel">
       <Version>1.2.3</Version>