If connection is not established, the Polly retry policy i HttpMessageHandlers are not called.

Hello,

why is not called Polly policy http message handler when connection could not be established?
I would like to retry even if connection could not be established, the service might be restarting when I'm doing the grpc call.

How can I add http message handler which will be called even during connection?

```csharp
serviceCollection
.AddGrpcClient(option =>
{
option.Address = new Uri(configuration.EndpointAddress);
option.CallOptionsActions.Add(ctx =>
ctx.CallOptions =
ctx.CallOptions
.WithDeadline(DateTime.UtcNow.Add(configuration.Deadline)))
;
})
.AddPolicyHandler(retryFunc);
```
This sample code was taken from past discussion https://github.com/grpc/grpc-dotnet/issues/686
```csharp
Func> retryFunc = (request) =>
{
return Policy.HandleResult(r => r.Headers.GetValues("grpc-status").FirstOrDefault() != "0")
.WaitAndRetryAsync(3, (input) => TimeSpan.FromSeconds(3 + input), (result, timeSpan, retryCount, context) =>
{
var grpcStatus = (StatusCode)int.Parse(result.Result.Headers.GetValues("grpc-status").FirstOrDefault() ?? "0");
Console.WriteLine($"Request failed with {grpcStatus}. Retry.");
});
};
```

Start with the AddGrpcClient(...).AddPolicyHandler(retryFunc) pipeline shown in the issue and the prior discussion in grpc/grpc-dotnet#686. Determine whether connection-establishment failures can enter the policy handler; the issue does not specify which files or tests should change, or whether the expected result is implementation or documentation.

Written by the indexing model from the issue text.