put lock around buildNewOnionPaths since it's called multiple times

js/modules/loki_snode_api.js

@@ -416,11 +416,10 @@ class LokiSnodeAPI {
     });
   }
 
-  // FIXME: need a lock because it is being called multiple times in parallel
   async buildNewOnionPaths() {
-    // Note: this function may be called concurrently, so
+    // Note: this function may be called concurrently
-    // might consider blocking the other calls
 
+    return primitives.allowOnlyOneAtATime('buildNewOnionPaths', async () => {
       const _ = window.Lodash;
 
       log.info('LokiSnodeAPI::buildNewOnionPaths - building new onion paths');
@@ -497,6 +496,7 @@ class LokiSnodeAPI {
       }
 
       log.info(`Built ${this.onionPaths.length} onion paths`, this.onionPaths);
+    });
   }
 
   async getRandomSnodeAddress() {