Benchmark client no longer compiles on .NET 9 #2499
Description
Many X509Certificate2 ctors have been marked obsolete in 9.0 and the gRPC client is using one of the obsolete APIs.
This is failing benchmark runs with the build error seen below:
/tmp/benchmarks-agent/benchmarks-server-1/6F579F9A7D95A5F7/perf/benchmarkapps/GrpcClient/Program.cs(479,45): error SYSLIB0057: 'X509Certificate2.X509Certificate2(string, string?)' is obsolete: 'Loading certificate data through the constructor or Import is obsolete. Use X509CertificateLoader instead to load certificates.' (https://aka.ms/dotnet-warnings/SYSLIB0057) [/tmp/benchmarks-agent/benchmarks-server-1/6F579F9A7D95A5F7/perf/benchmarkapps/GrpcClient/GrpcClient.csproj]