Bump Microsoft.Extensions.Http.Polly from 7.0.13 to 8.0.0 in /samples (#264)

Bumps [Microsoft.Extensions.Http.Polly](https://github.com/dotnet/aspnetcore) from 7.0.13 to 8.0.0.
- [Release notes](https://github.com/dotnet/aspnetcore/releases)
- [Changelog](https://github.com/dotnet/aspnetcore/blob/main/docs/ReleasePlanning.md)
- [Commits](dotnet/aspnetcore@v7.0.13...v8.0.0)

---
updated-dependencies:
- dependency-name: Microsoft.Extensions.Http.Polly
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

samples/CommunityToolkit.Maui.Markup.Sample/CommunityToolkit.Maui.Markup.Sample.csproj

@@ -44,7 +44,7 @@
   <ItemGroup>
     <PackageReference Include="CommunityToolkit.Maui" Version="6.1.0" />
     <PackageReference Include="CommunityToolkit.Mvvm" Version="8.2.2" />
-    <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="7.0.13" />
+    <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="8.0.0" />
     <PackageReference Include="Refit.HttpClientFactory" Version="7.0.0" />
   </ItemGroup>