fix: check for nil pointer in author id

internals/discord/bot/events/errors/messages.go

@@ -15,12 +15,17 @@ func NewMessageErr[E any](
 	msg *dgo.Message,
 	log *slog.Logger,
 ) MessageErr[E] {
+	var authorID string
+	if msg.Author != nil {
+		authorID = msg.Author.ID
+	}
+
 	return MessageErr[E]{&defaultEventErr[E]{
 		data: map[string]any{
 			"MessageID": msg.ID,
 			"ChannelID": msg.ChannelID,
 			"GuildID":   msg.GuildID,
-			"AuthorID":  msg.Author.ID,
+			"AuthorID":  authorID,
 		},
 		session:          s,
 		channelID:        msg.ChannelID,