Unable to view service invocation calls using .NET SDK in Zipkin

## Expected Behavior

When making a service invocation using either an `HttpClient` or the `DaprClient` in the Dapr .NET SDK, I expect to see traces of the invocation in my configured Zipkin instance.

## Actual Behavior

When making a call via the Dapr .NET SDK via `DaprClient` to perform service invocation, the trace does not show up in Zipkin. The following example is shared by "Gor Gasparyan" in Discord:
```cs
await _daprClient.InvokeMethodAsync>(HttpMethod.Get, "aoa-task-api", "taskapi/Examples/Frequencies", requestData);
```

Similarly, just calling the sidecar directly from an `HttpClient` in .NET also fails to show any traces in Zipkin. The following example is shared by @amolenk in Discord:
```cs
await _httpClient.GetFromJsonAsync($"http://localhost:3601/v1.0/invoke/vehicleregistrationservice/method/vehicleinfo/{licenseNumber}");
```

But both developers report that when sending the request to the sidecar using Curl, the trace is reported in Zipkin:
```bash
curl http://localhost:3601/v1.0/invoke/vehicleregistrationservice/method/vehicleinfo/40-GTG-3
```

## Steps to Reproduce the Problem

## Release Note

RELEASE NOTE: **FIX** Unable to view Zipkin traces using service invocation in .NET application

Start by reproducing service invocation through DaprClient and HttpClient, then compare it with the working curl request while checking the .NET SDK's tracing path and Zipkin reporting. Done means invocations from both .NET examples produce visible traces in the configured Zipkin instance.

Written by the indexing model from the issue text.