Fixed creating message with no self-member cached (#523)

Closes #522

Author: davidcole1340

src/Discord/Parts/Channel/Channel.php

@@ -704,8 +704,8 @@ public function sendMessage(string $text, bool $tts = false, $embed = null, $all
             ];
         }
 
-        if (! $this->is_private) {
-            $botperms = $this->guild->members->offsetGet($this->discord->id)->getPermissions($this);
+        if (! $this->is_private && $member = $this->guild->members->offsetGet($this->discord->id)) {
+            $botperms = $member->getPermissions($this);
 
             if (! $botperms->send_messages) {
                 return \React\Promise\reject(new NoPermissionsException('You do not have permission to send messages in the specified channel.'));

src/Discord/Parts/Channel/Message.php

@@ -322,10 +322,7 @@ protected function getAuthorAttribute(): ?Part
      */
     protected function getMemberAttribute(): ?Member
     {
-        if (($this->channel->guild &&
-            $author = $this->channel->guild->members->get('id', $this->attributes['author']->id)) ||
-            $author = $this->discord->users->get('id', $this->attributes['author']->id)
-        ) {
+        if ($this->channel->guild && $author = $this->channel->guild->members->get('id', $this->attributes['author']->id)) {
             return $author;
         }