fix: site replication issues and add tests (#13861)

- deleting policies was deleting all LDAP
  user mapping, this was a regression introduced
  in #13567

- deleting of policies is properly sent across
  all sites.

- remove unexpected errors instead embed the real
  errors as part of the 500 error response.

docs/site-replication/rw.json

@@ -0,0 +1 @@
+{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Action":["admin:*"]},{"Effect":"Allow","Action":["s3:*"],"Resource":["arn:aws:s3:::*"]}]}