StreamChatException.FromResponse crashes in case of Http timeout

[Benjamin]

When StreamChatException.FromResponse() is called in case of a Http timeout, JsonConvert.DeserializeObject<StreamChatException.ExceptionState>(response.Content) causes a Newtonsoft.Json.JsonReaderException.
The content of response.Content is in that case "Request Timeout".

gz#9477

[Stephen Hodgetts]

Agent comment from Anders Lund in Zendesk ticket #9477:

Hi there,

We'll take a look into this as soon as we can.

[Peter Deme]

#80