fix(search-backend-module-elasticsearch): correctly resolve error handling promise

Signed-off-by: Thomas Cardonne <thomas.cardonne@adevinta.com>

.changeset/afraid-ghosts-watch.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-search-backend-module-elasticsearch': patch
+---
+
+Fix never resolved indexer promise.

plugins/search-backend-module-elasticsearch/src/engines/ElasticSearchSearchEngine.ts

@@ -345,6 +345,7 @@ export class ElasticSearchSearchEngine implements SearchEngine {
 
           attempts++;
         }
+        done();
       });
 
       if (cleanupError) {