Fix language filter for data other than text

[syphax-bouazzouni]

Context

Follow up of https://github.com/ncbo/goo/pull/118

The issue is when in the ontology we set a lang tag for anything else than text, see example bellow

TODO

• [x] fix by forcing the casting to string in all the cases
• [x] update https://github.com/ncbo/goo/pull/118

Deployment

• [x] Testportal
• [x] Stageportal
• [x] Agroportal
• [x] Bioportal