[timefilter] ensure that the timefilter always has a default value

To reproduce the fatal error that occurs because of this bug, follow these steps

 - visit [http://localhost:8000/](http://localhost:8000/) in a new tab
 - click a time bucket to filter the data
 - click another time bucket to filter the data
 - click the back button twice

The issue appears to be that globalState isn't saved/replaced when the default timefilter is added. This means that at some point the globalState in history is empty, and the defaults need to be applied.