MAGE-1242 Split method for mixable search override

Alternate method to using `beforeInstantsearchInit` event

For details on why you might do this:  https://www.algolia.com/doc/guides/solutions/ecommerce/b2b-catalog-management/tutorials/personalized-pricing/#retrieving-the-pricing-information-asynchronously

Author: cammonro

view/frontend/web/js/instantsearch.js

@@ -1135,14 +1135,21 @@ define([
             return algoliaCommon.triggerHooks(
                 'beforeInstantsearchInit',
                 {
-                    searchClient: algoliasearch(algoliaConfig.applicationId, algoliaConfig.apiKey),
+                    searchClient: this.getSearchClient(),
                     indexName   : this.getProductIndexName(),
                     routing     : algoliaCommon.routing,
                 },
                 mockAlgoliaBundle
             );
         },
 
+        /**
+         * Initialize search client
+         */
+        getSearchClient() {
+            return algoliasearch(algoliaConfig.applicationId, algoliaConfig.apiKey);
+        },
+
         /**
          * Get raw search parameters for configure widget
          * See https://www.algolia.com/doc/api-reference/widgets/configure/js/