Chats propTypes fixes

app/soapbox/features/chats/components/chat_box.js

@@ -40,7 +40,7 @@ class ChatBox extends ImmutablePureComponent {
     intl: PropTypes.object.isRequired,
     chatId: PropTypes.string.isRequired,
     chatMessageIds: ImmutablePropTypes.orderedSet,
-    chat: ImmutablePropTypes.map,
+    chat: ImmutablePropTypes.record,
     onSetInputRef: PropTypes.func,
     me: PropTypes.node,
   }

app/soapbox/features/chats/components/chat_window.js

@@ -46,7 +46,7 @@ class ChatWindow extends ImmutablePureComponent {
     chatId: PropTypes.string.isRequired,
     windowState: PropTypes.string.isRequired,
     idx: PropTypes.number,
-    chat: ImmutablePropTypes.map,
+    chat: ImmutablePropTypes.record,
     me: PropTypes.node,
     displayFqn: PropTypes.bool,
   }