Add cmab error

Author: esrakartalOpt

lib/optimizely/cmab/cmab_client.rb

@@ -110,7 +110,7 @@ def _do_fetch(url, request_body, timeout)
 
       begin
         body = response.json
-      rescue JSON::ParserError
+      rescue JSON::ParserError, Optimizely::CmabInvalidResponseError => e
         error_message = Optimizely::Helpers::Constants::INVALID_CMAB_FETCH_RESPONSE
         @logger.log(Logger::ERROR, error_message)
         raise CmabInvalidResponseError, error_message