feat: name the HTTP status when the error body is not JSON

lib/getstream_ruby/error_mapping.rb

@@ -31,7 +31,7 @@ def raise_api_error(response)
       end
 
       raise ApiError.new(
-        message: 'failed to parse error response',
+        message: "failed to parse error response: unexpected server response code #{response.status}",
         status_code: response.status,
         code: 0,
         exception_fields: {},

lib/getstream_ruby/errors.rb

@@ -13,7 +13,8 @@ class ConfigurationError < StreamError; end
 
   # Raised on any HTTP 4xx/5xx response. Also raised when an HTTP response is
   # received but its body is not a parseable `APIError` envelope, with `code = 0`
-  # and `message = "failed to parse error response"`.
+  # and `message = "failed to parse error response: unexpected server response
+  # code <status>"`.
   class ApiError < StreamError
 
     attr_reader :status_code, :code, :exception_fields, :unrecoverable,

spec/errors_spec.rb

@@ -307,7 +307,7 @@
 
         expect(err.status_code).to eq(500)
         expect(err.code).to eq(0)
-        expect(err.message).to eq('failed to parse error response')
+        expect(err.message).to eq('failed to parse error response: unexpected server response code 500')
         expect(err.raw_response_body).to eq('oops')
 
       end