Fix: elasticsearch connection hardcoded (#10975)

### What problem does this PR solve?

https://github.com/infiniflow/ragflow/issues/10930

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

rag/utils/es_conn.py

@@ -75,9 +75,8 @@ class ESConnection(DocStoreConnection):
             settings.ES["hosts"].split(","),
             basic_auth=(settings.ES["username"], settings.ES[
                 "password"]) if "username" in settings.ES and "password" in settings.ES else None,
-            verify_certs=False,
-            timeout=600
-        )
+            verify_certs= settings.ES.get("verify_certs", False),
+            timeout=600 )
         if self.es:
             self.info = self.es.info()
             return True