Fix ArgumentOfRangeException with Discord message intents.
Created by: Neuheit
Summary
Fixes #633 (closed)
Details
This PR fixes the above issue by having the message cache be null rather than have it be 0 sized when supplying message intents. It also adds the appropriate null checks.
Changes proposed
- Makes the internal message cache null
- Adds appropriate null checks.
- Removes an obsolete user event from the DiscordShardedClient (not sure how it got there).