fix: 🐛 safely pulls lang from query params, defaults to english (#7662)

Co-authored-by: Carol Sachdeva <58209918+carol-deriv@users.noreply.github.com>

packages/core/src/Stores/client-store.js

@@ -38,6 +38,7 @@ import moment from 'moment';
 import { setDeviceDataCookie } from './Helpers/device';
 
 const LANGUAGE_KEY = 'i18n_language';
+const DEFAULT_LANGUAGE = 'EN';
 const storage_key = 'client.accounts';
 const store_name = 'client_store';
 const eu_shortcode_regex = new RegExp('^(maltainvest|malta|iom)$');
@@ -409,13 +410,11 @@ export default class ClientStore extends BaseStore {
             () => [this.account_settings],
             () => {
                 const { trading_hub } = this.account_settings;
-                const lang_from_url = window.location.search.slice(-2);
+                const lang_from_url = new URLSearchParams(window.location.search).get('lang') || DEFAULT_LANGUAGE;
                 this.is_pre_appstore = !!trading_hub;
                 localStorage.setItem('is_pre_appstore', !!trading_hub);
-                if (lang_from_url) {
-                    this.setPreferredLanguage(lang_from_url);
-                    localStorage.setItem(LANGUAGE_KEY, lang_from_url);
-                }
+                this.setPreferredLanguage(lang_from_url);
+                LocalStore.set(LANGUAGE_KEY, lang_from_url);
             }
         );
         // TODO: Remove this after setting trading_hub enabled for all users