`services.AddDaprClient()` should allow fluent registration

## Describe the proposal

The Dapr.AspNetCore package has an extension for registering the Dapr client using `services.AddDaprClient()` [here](https://github.com/dapr/dotnet-sdk/blob/764b4d7674296b3e1c3864de80e9fe6dd2d16b0d/src/Dapr.AspNetCore/DaprServiceCollectionExtensions.cs?_pjax=%23js-repo-pjax-container%2C%20div%5Bitemtype%3D%22http%3A%2F%2Fschema.org%2FSoftwareSourceCode%22%5D%20main%2C%20%5Bdata-pjax-container%5D#L31). Traditionally extensions like this will return the `IServiceCollection` provided so registrations can be chained:

```c#
services
.AddSingleton()
.AddTransient();
```

Unfortunately, the current method returns `void` so it cuts off the fluent registration support.

I'd like to propose changing that to return `IServiceCollection` to follow the registration conventions and allow fluent registration.

This would be a breaking API change from a binary perspective but not a source perspective - folks upgrading without recompiling would break, but if you recompile it wouldn't require any code changes. Potentially it could be scheduled for the next major release?