[Feat] Log Request metadata on gcs bucket logging (#5743)

* add requester_metadata in standard logging payload

* log requester_metadata in metadata

* use StandardLoggingPayload for logging

* docs StandardLoggingPayload

* fix import

* include standard logging object in failure

* add test for requester metadata

litellm/proxy/proxy_config.yaml

@@ -25,6 +25,12 @@ model_list:
 general_settings: 
  master_key: sk-1234 
 
+
+litellm_settings:
+  callbacks: ["gcs_bucket"]
+
+
 router_settings:
   enable_tag_filtering: true
 
+