Remove deadlocking in Member::highest_role_info
Remove deadlocking in Member::highest_role_info

Instead of calling `parking_lot::RwLock::read` on the member's guild,
call `parking_lot::RwLock::try_read` and return None early if it would
cause a deadlock.

zeyla/serenity,Flat/serenity,acdenisSK/serenity,zeyla/serenity.rs,Lakelezz/serenity