Fix OPA result response handling (#7763)

Also update the document with updated rego policy
and updated OPA agent REST API.

This PR is to fix a regression caused by PR #7637

docs/sts/putobject.rego

@@ -2,7 +2,9 @@ package httpapi.authz
 
 import input as http_api
 
-allow {
- input.action = "s3:PutObject"
- input.owner = false
+default allow = false
+
+allow = true {
+ http_api.action = "s3:PutObject"
+ http_api.owner = false
 }