Reduce E2E ES sync cluster from 2 workers to 1

Lowers concurrent pressure on Elasticsearch during daily E2E sync.
Affects both Sync_to_Elasticsearch and Sync_RAS_to_Elasticsearch tasks.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: caseydm

jobs/walden_end2end.yaml

@@ -300,7 +300,7 @@ resources:
             enable_elastic_disk: true
             data_security_mode: SINGLE_USER
             runtime_engine: STANDARD
-            num_workers: 2
+            num_workers: 1
         - job_cluster_key: Wunpaywall_DataFeed_Job_Cluster
           new_cluster:
             cluster_name: ""