fix(MessageReaction*Action): correctly cache incoming members and users (#4969)

src/client/actions/Action.js

@@ -93,8 +93,9 @@ class GenericAction {
     if (data.guild_id && data.member && data.member.user) {
       const guild = this.client.guilds.cache.get(data.guild_id);
       if (guild) {
-        const member = this.getMember(data.member, guild);
-        return member ? member.user : this.getUser(data.member.user);
+        return guild.members.add(data.member).user;
+      } else {
+        return this.client.users.add(data.member.user);
       }
     }
     return this.getUser(data);

src/client/actions/MessageReactionAdd.js

@@ -8,7 +8,10 @@ const { PartialTypes } = require('../../util/Constants');
 { user_id: 'id',
      message_id: 'id',
      emoji: { name: '<27>', id: null },
-     channel_id: 'id' } }
+     channel_id: 'id',
+     // If originating from a guild
+     guild_id: 'id',
+     member: { ..., user: { ... } } }
 */
 
 class MessageReactionAdd extends Action {

src/client/actions/MessageReactionRemove.js

@@ -7,7 +7,8 @@ const { Events } = require('../../util/Constants');
 { user_id: 'id',
      message_id: 'id',
      emoji: { name: '<27>', id: null },
-     channel_id: 'id' } }
+     channel_id: 'id',
+     guild_id: 'id' }
 */
 
 class MessageReactionRemove extends Action {