AddPerson search: fix aborting query when the query is altered by user

src/Bundle/ChillPersonBundle/Resources/public/vuejs/_api/AddPersons.js

@@ -45,7 +45,7 @@ const searchPersons =  ({ query, options }, signal) => {
 const searchEntities =  ({ query, options }, signal) => {
    let queryStr = parametersToString({ query, options });
    let url = `/api/1.0/search.json?${queryStr}`;
-   return fetch(url)
+   return fetch(url, { signal })
       .then(response => {
          if (response.ok) { return response.json(); }
          throw Error('Error with request resource response');