chore: increase retriever.test() timeout to 15s for slow initialization

Author: jlin53882

index.ts

@@ -3802,7 +3802,7 @@ const memoryLanceDBProPlugin = {
             );
             const retrievalTest = await withTimeout(
               retriever.test(),
-              8_000,
+              15_000,
               "retriever.test()",
             );