Exclude other bot users from the pool

[mjmammoth]

Currently, the random member from the channel chosen can be another slack bot which is undesirable.

When MusicalChair is added to a channel, it should scan for bot users using the users_info method of the slack_bolt sdk and add those bot users to the permanent exclusions state. This would also require for new members added to the channel to be acted upon, checking if it is a bot or not.

This should help achieve the desired outcome:

non_bot_members = [member for member in members if not client.users_info(user=member)["user"]["is_bot"]]