MINOR: [C#] Bump Google.Protobuf and Grpc.AspNetCore in /csharp

Bumps [Google.Protobuf](https://github.com/protocolbuffers/protobuf) and [Grpc.AspNetCore](https://github.com/grpc/grpc-dotnet). These dependencies needed to be updated together.

Updates `Google.Protobuf` from 3.28.3 to 3.27.0
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v3.28.3...v3.27.0)

Updates `Grpc.AspNetCore` from 2.66.0 to 2.67.0
- [Release notes](https://github.com/grpc/grpc-dotnet/releases)
- [Changelog](https://github.com/grpc/grpc-dotnet/blob/master/doc/release_process.md)
- [Commits](grpc/grpc-dotnet@v2.66.0...v2.67.0)

---
updated-dependencies:
- dependency-name: Google.Protobuf
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: Grpc.AspNetCore
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

csharp/test/Apache.Arrow.Flight.TestWeb/Apache.Arrow.Flight.TestWeb.csproj

@@ -6,7 +6,7 @@
 
   <ItemGroup>
     <PackageReference Include="Google.Protobuf" Version="3.28.3" />
-    <PackageReference Include="Grpc.AspNetCore" Version="2.66.0" />
+    <PackageReference Include="Grpc.AspNetCore" Version="2.67.0" />
   </ItemGroup>
 
   <ItemGroup>