from_config() ignores solver param

```
>>> client = Client.from_config(solver={'num_qubits__gt': 8000})
>>> len(client.get_solvers())
9
>>> client = Client.from_config(solver="no_such_solver")
>>> len(client.get_solvers())
9
```
https://docs.ocean.dwavesys.com/en/stable/docs_cloud/reference/generated/dwave.cloud.client.Client.from_config.html#dwave.cloud.client.Client.from_config states that `from_config()` accepts "**kwargs (dict) – Client constructor options" and https://docs.ocean.dwavesys.com/en/stable/docs_cloud/reference/resources.html#dwave.cloud.client.Client states that it accepts `solver` param.