Merge pull request #4848 from ritzalam/fix-chat-auto-reconnect

...src/org/bigbluebutton/modules/chat/maps/ChatEventMap.mxml

.../org/bigbluebutton/modules/chat/model/ChatConversation.as

...ent/src/org/bigbluebutton/modules/chat/model/ChatModel.as

...bigbluebutton/modules/chat/services/ChatMessageService.as

...ent/src/org/bigbluebutton/modules/chat/views/ChatTab.mxml