Error on response after modifying request API from _msearch to _search

**Affected Projects**: Reactivesearch / ReactiveCore

**Library Version:** 3.0.1

**Describe the bug**
Using the [Reactivesearch documentation as a baseline](https://docs.appbase.io/docs/reactivesearch/v3/overview/reactivebase/), I changed the request API endpoint as follow:
The request was processed nicely by Elasticsearch. However, the following error was thrown while the library was processing the response:
As I checked, the problem is that the **handleResponse** method tries to directly access a "responses" property from the body, and the search API doesn't return an array of responses - it returns a single response.

**To Reproduce**
Steps to reproduce the behavior:
Just modify any request using **transformRequest** as described above.

**Expected behavior**
The single response from the **_search** API should be processed succesfully.