vector: the ingestion endpoint is under /logs too

VictoriaLogs' -http.pathPrefix applies to every endpoint, not just the UI, so the elasticsearch bulk path is
/logs/insert/elasticsearch/. It rejected the writes with exactly that message. The other three references
(vmalert datasource, the metrics scrape, the deadman health probe) were already prefixed correctly.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

observability/vector.yaml

@@ -89,7 +89,8 @@ sinks:
   victorialogs:
     type: elasticsearch
     inputs: [parsed]
-    endpoints: ["http://victorialogs:9428/insert/elasticsearch/"]
+    # -http.pathPrefix=/logs applies to EVERY endpoint, ingestion included, so the bulk path lives under it
+    endpoints: ["http://victorialogs:9428/logs/insert/elasticsearch/"]
     mode: bulk
     api_version: v8
     compression: gzip