Handle rate limits in slack connector methodsearch_history_messages

[FabioRosado]

While working with @rodrigo-albuquerque on #1961 I've noticed that the method search_history_messages is also not handling any ratelimit exceptions (or any SlackApiError exceptions), we should do two things:

• remove the infinite look white True and use something like 'max_retries` set to 5 retries
• Handle any exception raised by slack when we call conversations_history and decrease max_retries (this will cause the loop to break)