Bump Grpc.Tools from 2.51.0 to 2.56.2

Bumps [Grpc.Tools](https://github.com/grpc/grpc) from 2.51.0 to 2.56.2.
- [Release notes](https://github.com/grpc/grpc/releases)
- [Changelog](https://github.com/grpc/grpc/blob/master/doc/grpc_release_schedule.md)
- [Commits](https://github.com/grpc/grpc/commits)

---
updated-dependencies:
- dependency-name: Grpc.Tools
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

test/Splunk.OpenTelemetry.AutoInstrumentation.IntegrationTests/Splunk.OpenTelemetry.AutoInstrumentation.IntegrationTests.csproj

@@ -11,7 +11,7 @@
 
  <ItemGroup>
  <PackageReference Include="Google.Protobuf" Version="3.23.3" />
- <PackageReference Include="Grpc.Tools" Version="2.51.0" PrivateAssets="all" />
+ <PackageReference Include="Grpc.Tools" Version="2.56.2" PrivateAssets="all" />
  <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
  <PackageReference Include="System.Collections.Immutable" Version="7.0.0" />
  <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="7.0.0" />