Destroy metadata popups on language change

Fix #1469 

It's a quick fix when we change the language we destroy all the popup. To make the popup reopened on language change needs a bit more refactoring of the service.


Test [here](http://mf-geoadmin3.dev.bgdi.ch/fix_metadata/prod/?lang=de&topic=ech&bgLayer=ch.swisstopo.pixelkarte-farbe&X=190000.00&Y=660000.00&zoom=1&catalogNodes=457,491&layers_opacity=0.75&layers=ch.bafu.biogeographische_regionen)