Highlight "Jump to Bottom" badge when appropriate

This resolves https://github.com/vector-im/riot-web/issues/13135

Signed-off-by: Mike Pennisi <mike@mikepennisi.com>

src/components/structures/RoomView.js

@@ -2044,6 +2044,7 @@ export default createReactClass({
         if (!this.state.atEndOfLiveTimeline && !this.state.searchResults) {
             const JumpToBottomButton = sdk.getComponent('rooms.JumpToBottomButton');
             jumpToBottom = (<JumpToBottomButton
+                highlight={this.state.room.getUnreadNotificationCount('highlight') > 0}
                 numUnreadMessages={this.state.numUnreadMessages}
                 onScrollToBottomClick={this.jumpToLiveTimeline}
             />);