chat: add connectionId presence item

Author: AndyTWF

src/pages/docs/chat/rooms/presence.mdx

@@ -103,6 +103,7 @@ The following are the properties of a presence event:
 | type | The type of the event | String |
 | member | The presence member that the event pertains to | PresenceMember |
 | | `clientId`: The ID of the client that triggered the event. | String |
+| | `connectionId`: The connection ID of the client that triggered the event. Use this in combination with `clientId` to identify a user across multiple devices. | String |
 | | `data`: Optional user data. | Object |
 | | `updatedAt`: The time that the event was emitted. | DateTime |
 | | `extras`: A JSON object of arbitrary key-value pairs that may contain metadata, and/or ancillary payloads related to the user's latest presence event. | object |