Show missing filename in load no-go areas dialog
Show missing filename in load no-go areas dialog

5b52abc1 copied `<label>` and `<input>` from the `loadedittrackForm` for
consistency, but missed to add some corresponding code to `NoGoAreas.js`.

After completing the implementation, the filename for loading no-go areas is now
displayed after selecting a file just like in the "Load track as route" dialog.

Test Plan:
- Open "Load no-go areas" dialog.
- Browse and select file.
- The filename should now be shown next to "Browse".

nrenner/brouter-web,nrenner/brouter-web,nrenner/brouter-web