fix: don't assume the member will always be included on MESSAGE_CREATE (#1167)
fix: don't assume the member will always be included on MESSAGE_CREATE (#1167)

* fix: don't assume the member will always be included on MESSAGE_CREATE

This resolves #1153.

Member objects are only included on a message when the user has
transitioned from an offline state to an online state (i think?), so
this change will fall back to the prior behavior, where we just create
an incomplete member object for these states.

* lint: use a ternary in place of an if/else block

AntiTcb/Discord.Net,RogueException/Discord.Net