Resolve "[Research] - Sort article by date not working"

Closes #79 (closed)

src/app/geosource/services/elasticsearch.service.ts

@@ -450,7 +450,7 @@ export class ElasticsearchService {
             },
           },
           {
-            'content-fr.datePublished': {
+            'content-fr.published_at': {
               order: options.sortOptions.order,
               unmapped_type: 'date',
             },
@@ -1034,7 +1034,7 @@ export class ElasticsearchService {
     if (options.sortDate) {
       requestOptions.body['sort'] = [
         {
-          'content-fr.datePublished': { order: 'desc', unmapped_type: 'date' },
+          'content-fr.published_at': { order: 'desc', unmapped_type: 'date' },
         },
       ];
     }